This seems like a hating thread, but so be it:
1. The Super Speedy Cider Squeezy 6000 - obnoxious brothers, the entire Apple family acting totally brainless, trite plot, OOC Pinkie. The song is good but it's not enough to want to see this least favorite episode of mine disappear forever.
2. Somepony to Watch Over Me - totally OOC AJ, overused plot. The Chimera isn't enough to save it. Buh-bye.
3. Leap of Faith - this episode wasn't horrendously terrible like my #1 pick above, but I really don't want to ever see the Flam brothers again, except for maybe chained to a wall in Twilight's dungeon. And Granny Smith is probably the least interesting character in the show, so that doesn't help this episode, either.
And yes, it's true. I would rather watch "Princess Spike" over "Leap of Faith" or the other two episodes above, even though it suffers from the same cliche plot and brainless character syndrome like the ones above. I generally avoid it when I can.
Same goes for "Spike at Your Service." At least it had a cool start and it's pretty good past the scene of Spike trying to fix Rarity's sink. I swear I'm going to sit down and make an edited version of that episode someday that just dumps the 7 minutes or so of Spike acting incompetent, then it will be a really fun watch.
Also "Spike at Your Service" has the honor of originally having a Dave Polsky treatment that instead featured him being a competent helper for Rarity, but that script got tossed for some reason.