Ah, "Look Before You Sleep". This episode had everything!!!

1) A showdown that was bound to happen sooner-or-later (i.e. AJ vs. Rarity), and was handled spectacularly by the creators!!! With such polarizing and dynamically opposite personalities, AJ and Rarity's differences needed to be addressed in order to show that they themselves could truly be friends with each other, and not just friends with Twilight, and this episode solidly accomplished that. Applejack in particular came across as particularly mature, although the antics between her and Rarity were absolutely hilarious!

2) This was also a great Twilight episode, actually!! It was one of the first episodes where she was both a supporting character, but we also got to see her (in her adorkable fashion) trying to learn more about friendship, and being extremely cute in the process!!!! You could just tell she'd wanted to throw a slumber party since she was a filly, even if she didn't say so!

3) One... Bucking... Epic... Pillow fight!!!!!!

4) This...

5) And finally, s'mores, and really, we all know that everything is 20% tastier with s'mores!

Overall, "Look Before You Sleep" is a great early episode that slightly deviated in more ways than one from previous episodes in its execution, with only three of the Mane 6 featured the whole episode and a lesson being learned by not one but two characters, further strengthening their unusual friendship. One of my Season 1 favorites, and always worth a rewatch to be sure.