The Sweethearts of Late Night Television

In particular, in an interview with TV Insider, Leno took time to praise Seth Meyers, Jimmy Fallon and Stephen Colbert (“a truly nice guy and decent human being”) before taking aim at Jimmy Kimmel, who has been a vicious and relentless critic of Leno over the years.
“The most [important] element you can have in doing a late night show is kindness,” Leno said. “Because the show makes you arrogant. I think that’s Jimmy Kimmel’s problem. I think he’s a talented guy, I think he’s funny. But he has a mean streak, and it comes across. He does this thing where he takes Halloween candy from kids and the kids cry. What am I missing here? It is funny I guess, but it’s mean-based. I think that’s why he’s not higher in the ratings.”
So, the most successful person in the history of late night television--Johnny Carson--was "nice?" 
Bushkin, who didn't return calls, says age didn't mellow Carson, who retired from "Tonight" in 1992. On a honeymoon cruise, his fourth wife, Alexis, made an innocent remark, prompting Carson to snap, "If you say something like that again, this marriage won't last another three weeks."
Though Carson's 20-year friendship with Bushkin ended around 1987, when Bushkin began to see Johnny's "cruel side" more often, Alex stayed married to the talk deity till his death in 2005.