I've never seen acting as lonely. Sure, you've got the solo time practicing lines and voices and body language, but that's just preparation. When you get to the stage (or the set), you instantly become a part of a community. I have a saying: "Backstage is backstage, wherever you go". Any time you get a bunch of theatre or film people together and give them a project to work on, you get the same result: lots of fun, lots of memories, some new friends, and (hopefully) a great show. That's why I act, for that universal community that I know I'll find on every stage and every set.