I hated Avatar. Probably because I didn't see it in 3D, but it was so ******** boring and long and preachy and generic oh my god.
Also, I just recently saw Videodrome and I don't get what's so good about it. It seemed really generic to me, too.
twilight(not mediocre, I just hate it)
Harold and Kumar
the dark knight
romantic comedies(because they never really are "comedies" just romance)
any movie with marijuana as a theme
any of Tyler Perry's movies
Titanic. On top of being predictable as ******** from the very beginning, it doesn't sit well with me that James Cameron felt the need to invent people who didn't exist in order to make us care about a historic tragedy. Why not just tell the stories of the people who were actually there?
The Dark Knight
How To Train Your Dragon
Star Wars (all of them)
Any movie with marijuana as a theme (Stole this one from Sgt. Frosty, but I feel the same way)
Donnie Darko and Lost Boys, I still have yet to meet somebody else who thinks they're horribly overrated.
As well as any of the live action Batman movies (yes this inclues Christopher Nolan's work). Mask of the Phantasm, SubZero, and Return of the Joker are still the only legitimate Batman movies in my book.
Definitely Avatar. My stepdad was all excited for the movie and I kept telling him was awful, predictable, scientifically inaccurate and most of all, a rehash of several other movie plots. But he kept saying he was excited to see it and I was stupid. But then... He saw it and absolutely hated it. He said it was almost as ridiculous as Indiana Jones and The Kingdom of the Crystal Skulls.
As for me, I think Spirited Away and the new Marvel movies are just... Not as interesting as people make them out to be. I mean, each Iron Man movie had awful villains and Thor just straight up sucked. Up, Toy Story 3 and X-Men: First Class were just all totally overrated.
And Prometheus looks like it'll be joining the club.