What is theater?

Theater is a performance, usually put on by a group of people (though there are one-man shows), taking on the roles of characters, for an audience. The actors get to become someone else, even if that person is a ficitonalized version of themself in the case of an autobiographical play. They can express and release heavy emotions through their performance, or just have a fun time getting to do stuff they couldn’t or wouldn’t in real life. There are other ways to participate in a play: helping with the lighting, sound, set, costumes, props, or being a member of the stage crew. No matter the size of your role, it feels satisfying to see everyone’s hard work come together, and those involved come to have a greater appreciation for the value of cooperation. 
The audience gets to experience the story unfolding life in front of them. It feels much more personal than sitting in a big cinema, watching flat characters on a sceen. And where re-watching a movie is largely the same experience, with it being dependent on the viewer to notice stuff they missed the first time, with a play, not only can you have different actors giving their own take on a character, but because it’s live, there might be other subtle changes that add to the freshness of it.
For me personally, I enjoy having an audience and being able to show off sides of me most people are unaware of. I remember multiple faculty coming up to me after we did Les Miserables last year to express how surprised they were by my intimidating performance as Javert. I have a lot of fun putting scenes together with my fellow actors at rehearsal, but I’m still working on letting go of my perfectionist tendencies and cutting others some slack rather than getting so easily frustrated with them. We always manage to pull it all together in the end, and it often comes out even better than the setup I had fixed in my head. I need to have more trust in the rest of the team. The last thing I’d want is to give off the impression that I think I’m better than everyone else.