By way of Science Daily (and ScreenDigest): A new study has shown that people's enjoyment of films correlates to other audience members. If the audience likes a film, you are more likely to like it, and you are more likely to like the same film if you watch it in a group. Seems that people really are copycats, and tend to gauge the reaction of others in the room and mimic their feelings (as expressed in their body movements and facial expressions):
"When asked how much they had liked the film, participants reported higher ratings the more their assessments lined up with the other person," explain Suresh Ramanathan and Ann L. McGill (both of the University of Chicago). "By mimicking expressions, people catch each other's moods leading to a shared emotional experience. That feels good to people and they attribute that good feeling to the quality of the movie."
They continue: "Social effects described above were bi-directional suggesting that such influences were mutual rather than the result of a leader-follower pattern."
It appears that this is also true for not liking a film - if the audience hates it, you'll be more likely to hate it as well. That said, the study confirms what many cinephiles have known for awhile, that there is something to watching a film in a theater.