Off the top of my head, Somepony to Watch Over Me, Rainbow Falls, Mare-Do-Well, Equestria Girls (especially >(), It Ain't Easy Bein' Breezies, and Owl's Well are some of the FIM episode that don't deserve the praise they get.
I don't think that's a good way to put it, because it's all about perception. You're a critic, so you notice all the flaws, but many more casual watchers don't. I'm not saying you're wrong, but I can't really agree either despite my dislike for some of them.