These are all wonderful! I'm pretty new here and I've read all nine pages of this thread. So many great quotes!
I could never choose a favorite. But I recently saw "White Gold" (Season 3, Ep 23). I love the exchange between Henry and Frank concerning Col. Flagg:
Frank: Well, Flagg wanted to get on with his torture, and, you know, three's a crowd.
Henry: Well I'll not have anyone tortured at the 4077th, Frank. WE'RE A HOSPITAL!!!
Frank: Well, uh...He ordered me to leave. He's a superior officer.
Henry: He's a superior psycho. His head's so twisted, he's gotta screw his cap on.