This is not related to chat, where caps is totally not appropriate, but this refers to typing in general. People talk about having capslock on when they're angry or excited, but it's not capslock I use to show my outrage. It's my pinky savagely holding down the shift key.

AND THAT IS WHY IT IS SO DAMN CATHARTIC
MMMM FEEL THAT CATHARSIS
IT'S LIKE I'M AT A MOTHER******* DAY SPA HERE
THE TENSION IS JUST FLOWING OUT OF ME I FEEL SO GODDAMN REFRESHED!
F***!
Okay the asterisks ruined it.