Note: Credit goes to @Cwanky for this review.

For the first time, FIM brings back a celebrity guest: Patton Oswalt. When I first watched Stranger Than Fan Fiction, I panned the character he voiced (Quibble Pants), calling him a stereotype of superfans and for being so dumb to think he's still near the Daring Do convention despite being in a radically different climate. Upon reflection, he's nowhere nearly as bad as I claimed. Holding onto the idiot ball in Act 2 is a big flaw in the episode, but he's no stereotype. Yes, he can be obnoxious, but he cares for the product. (Thank Fame & Misfuckton for helping me change my mind.)

Common Ground pushes forward new ground (pun unintentional ) for Quibble Pants in my favorite role of him so far. From the get-go, he fails to hide a inferiority complex, screwing up basic buckball knowledge and sports puns. But the second Clear Sky and Wind Sprint arrive, he shows a side from him we never see before: a devotion to his girlfriend and her daughter. For the first time all series, FIM tackles stepparenting, specifically the development of one. Haber marvelously intertwines his façade and desire to make the relationship work, notably to impress Wind Sprint and get her to like and appreciate him. And it's in their introductory scene do we see how important Quibble is to their dynamic, notably when Wind tries to sneak into the buckball stadium.

Quote

Clear Sky: *catches Wind* No! *uses her magic to drag her back to the museum line* Quibble planned this whole thing for us, and you could be a little more appreciative!

Quibble planned the trip, both to the museum and stadium. Regardless of his knowledge, he knows Wind like sports and to play them. The Hall of Fame in Appleoosa is a mark of excellence for Equestria's growing sport and foreshadows both her talent in athletic competition and love for her biological father (back to this point later). He researches his material and tries to apply the resources he has to make her happy, which becomes more evident by buying that humongous buckball almanac for her. Unfortunately, his effort ends up deflating her and further exposes him as a try-too-hard to Wind.

By pleading for help, Q shows that he's at his wit's end. He wants WS to like him, but no matter how much he tries, she only ends up detesting him more. Self-confidence from STFF was replaced with desperation and a cry for help. In a brief eye-to-eye, Clear Sky reminds him how he doesn't have to try too hard to get her to like him, further alluding the idea that he tried to impress her many times before. Planning this trip was likely his final shot. Luckily, Dash was there, and she's one of Equestria's most athletic ponies, so it can't be all bad…can it?

Ummmmm…

All of this leads to the episode's biggest flaw: the pitch scene. Wind Sprint's extremely skilled in buckball, perhaps better than Flutters, Pinkie, and Snails. Unfortunately, Quibble isn't, so there's a huge difference, even though Team Ponyville eased their skills to make things more fair. Seeing him so lost on the pitch means he fails so easily, and that sometimes makes it rather hard to watch. That said, it's a billion times tamer than Spike being forced to sing the Cloudesdale Anthem, which makes him out to be both Spike and SA dumb enough to assume Cloudesdale lost and let him take the mic, respectively. And Quibble actually not only tried to be better, but successfully bucks into his own net (and calls out a vaguely-written rule in the almanac, so he may suck on the field, but understands some of the game's basics from the outside).

But we can't talk about Quibble without Dash, Wind, and Clear.

Outside of Complete Crap Clause, Rainbow Dash has been on fire, and CG's no exception. After a poor start three seasons ago, they're now friends, and it shows through their exchanges early. When Q stumbled or screwed up sports phrases, she got confused or corrected him. But when he pleaded for help, she immediately accepted the offer. Why is she outstanding? Because it balances her flaws with her strengths. To describe what I mean:

1. She believed everypony has a sporty side in some way. Through Operation: Sportify, she worked tirelessly with him (once with Snips's help). Sadly, not everyone is so athletic. But when she couldn't find it immediately, she planned to have him and family work together as a team so he can work with WS. However, shoving him under the spotlight in front of tens of thousands of passionate fans wasn't the wisest decision, albeit with good intentions.
    
2. Her speed, athleticism, and agility come naturally for her. So when she shows off how well she can turn the corners while flying, she quips:

   Quote

   "Heh. Of course, some ponies can do it all."

   A little conceited? Perhaps. Then again, she's so skilled that what she does is normal, so when others can't, it's a surprise. But the episode cleverly juxtaposes this, displaying an understanding that he can't do all, so she starts small with plans to train him once he improves. All day, what does she do? Help train him. She wants him to improve, even by the lightest amount, and help him unite with Wind.

3. But her biggest testament to her character comes after Wind rejects his efforts and runs away from the pitch. As he disappointingly rummages through her present, she tries to regain his confidence by assuring him of other sporty ideas to help his athleticism. After finally letting his frustrations out and (on assumption) getting ready to quit his relationship with Clear, she offers him her best advice so far:

   Quote

   "But maybe I'm not the pony you should've come to for help."

   Short, sweet, and to the point.

Wind Spirit, the little filly in the episode, adds so much to the episode. When she doesn't say much, she shows her disappointment and disdain for him. Take a look at the first few seconds.

On first impressions, she looks like a little brat who's spoiled and with very specific tastes. The Hall of Fame museum bores her due to lack of action, preferring the tournament instead. But Clear Sky calls her out for misbehaving, only to eventually have Dash agree with her (cutting herself off after Q glared at her). Once inside the museum, the episode raises the stakes instantaneously, beginning with Q's confusion of sports and ending with this:

Quote

Rainbow Dash: Well, I figured you weren't the sportiest pony in Equestria.

Quibble Pants: But Wind Sprint is, and her dad was some big athlete, too. I-I can't compete with that. I really want things with Clear Sky to work out, but if Wind doesn't like me, I-I might as well give up.

From this point forward, the episode has a very clear goal: get Wind to like him.

But take a look at Q's first line, which says her biological dad was athletic. Two things come out of it:

1. With her father being athletic and really into sports like her, Quibble is left out of the loop. She sees him as a stranger, because he isn't what her dad was like and that he tries too hard to be like her dad that he comes off as phony. Hence her glares and sarcastic "thanks."
2. Her dad isn't there anymore. Usually, when someone's referred to in past tense, they're telling us they passed away or sometimes divorced. From the way he speaks of her, she's not happy that he's the opposite of who her dad was and doesn't appreciate him. Later moments, including her disappointment of him when he got stuck in a buckball basket, learning he bought her a book, and Quibble trying to impress her, add more into the conflict.
   
   Compared to Pear Butter and Bright Mac, we don't know his fate, and Patton Oswalt said on "Conan" prior that Clear and her husband (likely) divorced. But aside from past tense, two points hint his passing: Wind reminiscing of him while talking to Dash and Clear showing how much she still loves him.

But when Q's not nearby, Wind's attitude changes. After Dash meets her, she gets so excited and loves how well she can fly. Throughout the day, she's really happy to just be with Clear and watch the matches from the stands…only to scowl the second he returns from training. Despite exciting her with an offer, she doesn't hide her feelings for him before turning to Pinkie and FS glowingly:

Quote

Wind Sprint: *rolls eyes* Ugh. *glares at Quibble * Knowing sportsponies isn't the same as being one.

Recall what this episode is about: He's trying to get her to like him by making her believe there's more to them than what she truly sees. He doesn't understands sport or look sporty, but he can be and will prove it. But the harder he tries to hide his insecurities, the more she'll repel from him. By hiding behind an obvious façade, he's disrespecting her. Consequently, she justifiably insults him for being phony.

Her limit's finally pushed after Quibble scores an own goal and tries to argue otherwise so they keep playing:

Quote

Wind Sprint: I don't want to! You're not a sportspony! It's not fun playing this game with you!

Thanks to his plan and screwing up so poorly, it's not fun playing on the field with him or Snips. If playing it wasn't fun, then what's the point of going to it in the first place?

This leads me to the episode's glue, Clear Sky. With Quibble Pants and Wind Sprint eccentric and rather cartoony, a mellow head like her's necessary to balance the cast, and Haber handles her so well. Clear Sky adores Quibble Pants for being kind, smart, selfless, and hard-working. When they show disagreement, she keeps them all in check, such as Clear reminding Wind to appreciate his efforts to bring them all to the HoF. Instead of one-dimensionalizing her role, Common Ground rounds her by reassuring Quibble when he's down and unconditionally supporting Wind.

Her best moment occurs near the end after Wind and Q's relationship all but fell apart permanently.

Quote

Wind Sprint: I wish we didn't even come here.

Clear Sky: Quibble thought you'd like it.

Wind Sprint: Well, I don't, *turns to Clear* and I don't like him. Why do you like him?

Clear Sky: Because he's kind, and smart, and his friends certainly seem to care about him, which is always a good sign.

Wind Sprint: I don't care how many ponies care about him. They're not gonna make me forget about Dad. *stomps hoof, looks away*

Clear Sky: Oh, sweetheart. *places hoof on her back* I know Quibble's trying too hard, but he doesn't want you to stop loving your dad. He just wants you to like him. And I think maybe there's enough room in your heart to do both.

Wind's spirit was at her lowest all episode, her dislike towards him devolving towards bitterness. She wasn't simply disappointed in having him as a stepdad, but embarrassed, too. She's proud to be the daughter of an athletic dad, but he isn't around anymore, and now her new "dad" is an un-sporty pretender. The dialogue underlined my me, though, is the key to not only the exchange, but the evolution of her and Quibble's relationship. To echo @Cwanky, Wind misses her dad, wishes to have him around, and the episode doesn't look her down for it at all. Fear She fears Quibble will not only replace his dad physically, but in memory, too. Those memories of him hold dearly to her, and the prospect of Clear's new relationship with Q forcing her to throw them all away kills her. She doesn't want that.

Neither does Clear. From her motherly reply, she still loves him just as much as Wind Sprint and would never trade that away at all. After all, her relationship with him led her to mother Wind, who her husband resembles a lot of in her eyes. But that doesn't mean she can't love another stallion, even if he and Wind's dad share nothing in common. She loves him because he loves those around her and wants to make things right for her and her daughter. At no point does she want Wind to assume Q will treat her or her memories of Dad as an afterthought, and she doesn't want Wind to believe her fears are silly. They're not. By treating her fears seriously, the episode treats those who relate to her dilemma the same. Wind's experiences and feelings parallel those in real life, and Clear's words of comfort allow her to heed her own fears, grieve, and potentially welcome a really sweet stallion who deserves another chance.

This episode also mirrors plenty from what happened to the Oswalts, too. In 2016, Patton's first wife Michelle McNamara died in her sleep, leaving him and her daughter Alice (Wind's voice) behind. One year later, he married Michelle Salenger (Clear's voice), who posted this little tear-jerking recording of herself and Alice for this episode. Reading and watching what happened behind the scenes (including this chain from Big Jim) really helps me appreciate this new classic.

On the surface, it's a "be yourself" moral, but in reality, it's more than that. Besides not letting your own fears create a barrier from welcoming people to your family, don't pretend to know a passion in order to feel like you're a part of one. Dash was the Mane 8 featured, but she didn't have to learn the lesson. This was Quibble's episode, and his actions worsened the divide and threatened his relationship with Clear. To fix it, he had to own up to it to WS and work together to resolve their tense conflict.

Bittersweet it is, leaving the ending more open than traditional's the right call. Wind's wounds ran deep, so her bitterness won't disappear immediately. That almanac (a great callback to his love for Daring Do) foreshadowed that slow mending of their relationship. He may not physically play buckball, but became unknowingly knowledgeable of it from reading it and absorbing the analytics. As a result, Wind read it for herself, understood Team Ponyville's patterns, and realizes that by reading together, they can learn from each other and bond off the field. Now, do they have more to go? 100%. But with Clear supporting them, they're on the right track.

^ If this ending doesn't warm the cockles of your heart, I don't know what will.

I can write more about it, but I'll leave it here. Common Ground's a fantastic episode and will go down as one of FIM's best.