A recent experience of mine:
I was trying to perform some close-up card magic to some friends of mine, and encountered some of the worst heckling I've ever encountered. (I know, it gets a lot worse than this.)
I tried to perform a trick with a solid storyline, opening with a perfectly natural riffle force, natural because I was offering to someone just too far away to offer a fan... "No! Don't take that card! Take this one!" *grabs deck, removes card* I scoop up the rest of the deck, and explain that I don't generally perform under those conditions, as it disrupts my flow. "Go on, I bet you can't find this one. Just go on with the trick." "If I were to tell you that there was a perfectly good narrative reason for cutting the deck like that, would it make a difference? I'm not doing a story now, am I? I'm just rising to your challenge." He looked a little smug, but I could see the other spectators start to turn against him. I did what may have been a mistake, and rose to his challenge, in the hope that it would buy me some peace. "Ok, cut off any number of cards from the deck. Drop your card on top. Slap the rest on top, burying it. Good." "Can I cut the deck?" "Of course you may. Cut it again if you must. So you agree your card is lost?"
"Can I shuffle them?" "I think that's enough, don't you?" A laugh and a smile goes a long way, because he didn't resist me taking the deck from him. I gave the cards a quick shuffle, and Long Distance Spinnered the selection, caught it, and handed it to him. "Happy?" He frowned and looked through the cards for a while. "Wait, look at this! My card has a bend in it!" Shows insignificantly small bend in one edge of a card. I observe "Weren't you the only one who handled that card? You put the bend in yourself!" I noticed everyone else was starting to find this funny, and realised that as I was never going to get through a trick with a proper plot, I might as well destroy this guy. None of us were particularly keen on him to start with, and the others could see that he was spoiling it for them. So, I went for broke, and performed "Think of a card" from AOA1. Minimal patter. "I can't trust you not to change your mind, so I'll commit to this card, but you've got to name your card now. That seems fair......Really? Well, you aren't going to like this, but you can TAKE YOUR THREE OF DIAMONDS AND SUCK ON IT!"
Heckler:
every other spectator:
We left him sitting, staring forwards, stunned.
Thinking about it afterwards, I think I did the right thing. I entertained thoroughly everyone except for the one who refused to be entertained, who I may have granted a valuable experience, a moment of true astonishment

I don't think his opinion of magicians will be any worse, as it was already pretty low. I really don't like taking a confrontational magician vs. heckler attitude, but I think in this case I had no other choice, I gave him a few chances for redemption, and my other spectators were thoroughly amused.
Did I do the right thing? What would you have done?