Everyone's heard of hecklers, but I find that for all the discussion about them, they are actually exceedingly rare. (The most famous instance of heckling came at a one-nighter at a Holiday Inn in the South, I believe, where a customer was heckling a guitar act. The comic stood up, picked up his guitar, and smashed it over the audience member's head. The guy sued the booker, the hotel, and the comic for a bundle. There used to be a copy of the video on the Internet; if anyone knows the link, PLEASE email me and I'll post it. The link that I had is no longer working.) I have only a experienced a "true" heckler one time in my career, while doing a guest spot in a bringer show in New York City. There are a lot of stock lines -- "I don't come to where you work and knock the broom out of your hand" is one of the tamer ones -- but generally your best bet is to ignore them once, be polite a second time, and go after them the third time. By the third time, the audience will likely be fed up enough that they will stay on your side if you really go after the guy. (Unless you're just bombing, in which case you're in trouble.) If you take your shot at him, and get him to quiet down, you'll be fine. If not, hopefully club management will step in and handle it for you.
Moaners
There was a very funny episode of Seinfeld where Kramer's girlfriend ruined Jerry's show by laughing entirely too loud and at odd moments. Audiences are such odd, fragile beings that little things like that CAN seriously disrupt the flow of a room. I recently did a show in Chicago, and there was a young woman on the right side of the room who would moan after every joke. Not an out and out moan, but a girlish little squeak, like a 12-year-old girl seeing a kitten curled in the corner. Every time she did it, the laughter in the 40-person crowd came to a dead halt. I was only doing a guest set, and didn't have the time or the credibility to go after her, but I wish I could have.
