What Movies do you Hate that Everyone Else Loves?
Star Wars, by a staggering margin. My appreciation for Lucas's genius is for different aspects of it than most others' views of his work.
Top Gun, as well. Gay cinema can be so much, much better.
The Talented Mr. Ripley. One of the few 4-star reviewed movies I remember both my wife and I looking at our watches and each other about 1/2 way thru.
On the other hand, the first time I saw The Blues Brothers I thought it was one of the dullest, dumbest, most heavy-handed things I'd ever seen. I was forced to watch it again a couple of years later, and now about 20 viewings later I now think it's a masterpiece. So go figure.