I almost always go to the movies alone. I don't have to put up with people asking me "What just happened?" or "Could you give me a dolar so I can get some more soda?" or "C'mon, dude, I may have eaten my popcorn and said you were wasting money buying the bigger size, but can't you share?" (I may have been paraphrasing the last one, but that was the situation.)
Maybe it's because I had some bad experiences, but I only go to the movies with others if they're paying for my ticket. Plus, on time I went to a movie that was barely showing anymore, went in, and I was the only guy there. It was like having a private theater, and I made all the comments and noise I damn well felt like. After that, comparing it to the last time I went with others, I decided on my policy.