Paris Hilton (September 28, 2007)
The knock on Letterman is that he's "too mean" — a charge that's ridiculous since what makes Dave great is that he cuts through the nicey-nicey nonsense of most chat shows. That said, he was spectacularly cruel to Paris Hilton during this fall 2007 appearance. The celebrity wanted to promote her latest fragrance, and Letterman couldn't have cared less. After a couple disinterested questions about New York versus Los Angeles, the host gets right to it: "How'd you like being in jail?" Needling her about her short recent prison stint for driving with a suspended license, Letterman never lets up, even after Hilton curtly insists she's not going to talk about it anymore. (Thankfully, not before he asks, "Have your friends treated you differently since you've been out of the slammer?") Dave later apologized, but we owe him many thanks for not playing ball with a blatant image-rehabilitation project — as well as for that moment when the host drinks her dumb perfume.