Stiiiiiitch!!!!! There are others I may not care about, there are some I've never done (RnRC) 'cause they're "wilder" than I like, but Stitch is the one that makes me say "Why is this even still here?"
I hate the basic premise: let's trap you in a chair and turn out the lights and DO things to you. And it's just lame (not a word I bandy about).
Like a PP, I also find it frustrating: "Lilo & Stitch" is a really good, charming, underrated movie, and I love the characters (I still miss the Pleakley statue that used to be in Tomorrowland; I love Pleakley!). There ought to be a really fun Stitch-themed ride in Tomorrowland, but this ain't it.
(PS, I LOVE Small World! It is a Must Do for me, sometimes more than once! Come on, sing it with me....)