When I'm alone, I would make up songs in my head and if it sounds good I would hum and then sing for a bit. xD
When I'm alone in public, I sing to myself about everything that's going on around me.
"That dude looks kinda creepy, but it's okay because I'm going the other waaaaaay~" is a fine example.
It helps me feel less anxious about being outside/around people I don't know.
When I die in a video game, or when something goes wrong in it whether it's my fault or not; my favorite word to say is, "Ass!"
Sometime's I'll say it in a sentence. For instance I might say, "What an ass!"