23. Don Rickles
Don Rickles is a rare comic who found his voice by actually ignoring his material. In the late Forties, the man also known as "Mr. Warmth" and the "Merchant of Venom" discovered that his audiences connected more to the ad-libs he used to shut down hecklers than the jokes he'd written. Since then, the quick, sharp and unpredictable Rickles has plowed into his audiences, picking up on cues large and small and delivering little barbs ("It's over, I'm a friend") to his targets. Eventually, his wicked wit hit their most important target in Frank Sinatra, who championed the comedian to famous friends and got him started in Vegas. With that wide, jack-o-lantern mug and a torrent of rapid-fire gags, Rickles created a template that insult comics have referred to since the 1950s. This is how you do it right, hockey pucks.