I've had a lot of trouble with this, too; I'm very polite when interacting with strangers, servers, and CSRs. I've been re-training myself to say, "Okay, great," instead:
*Ready for the phone call to end* "Okay, great."
*Gets handed a receipt* "Okay, great."
*Drink gets refilled by server* "Thank... uh, okay, great... uh, I mean awesome. That wasn't awkward."
"The future ain't what it used to be." --Yogi Berra