Applauding After a Movie

Yesterday after the movie, many people clapped. I have never and will never understand why people do that. If we saw a live production on Broadway, then yes, you will clap when it's done. You don't clap after you see a movie in a movie theater. Do you clap when you watch a movie at home? Do you clap after you see a TV show? Do you boo if you don't like the movie? I find these things very strange. Luckily no one was clapping after the movie I saw today. I want my two hours back. My friends wanted to see Percy Jackson and I unfortunately went with them. Luckily I had a free movie pass. That movie was not my type at all. No matter how much I like a movie, I'm not clapping after it's finished.