I like it when I go to see a movie that comes highly recommended by several friends and I actually like the movie. It gives me some faith in humanity (well, in my friends anyway, the most important part of humanity), to see that people's taste in movies make some kind of sense to me.
When I go to see a movie my friends liked and I end up hating it, it always leaves me wondering, just a little bit.
For the curious, this was prompted by Eternal Sunshine of the Spotless Mind, which I liked, and Lost in Translation and Punch Drunk Love, which I did not enjoy at all.