I find that humor works better than confrontation. In the case of a heckler, one of the best remarks I ever heard was "That's ok, I remember my first beer."

As far as someone saying, "You are leaving out a chord." or "That's not the right words". If they can show me the RIGHT way, I just accept it as the truth, and I can't argue with the truth. I might reply, "Well, you learn something every day." Don't let them see you sweat. Most of all, don't let them reduce you to their nit picking attention demanding level. CH, that was NOT aimed at anyone in particular.