I always sit my myself when I go to the movie theater. I'm one of those people who is really particular about "my space". I don't even like sitting next to people on the bus if I can help it.
As for coming to a place of worship and talking, that is also a pet peeve of mine. It use to drive me up a wall when I would try to listen to the sermon and women would just talk and talk and talk. Sometimes I wanted to hold up a sign that said "STFU!" Fortunately, this isn't an issue where I currently worship but I think part of it is due to the design of the mosque. You couldn't really talk during the sermon without literally disturbing everyone.