Jack Paar — Johnny Carson's predecessor and the second host of The Tonight Show — was known for speaking his mind. In 1960, he quit the program in the middle of an episode because one of his jokes was censored. "There must be a better way to make a living than this," Paar huffed. (He returned a month later after a sobering realization: "Well, I looked ... There isn't.") So it comes as little surprise that Paar was a controversial guest. During Leno's weeklong tribute in 1994 to the show's roots, Paar very publicly informed Jay that he didn't like Madonna, an upcoming guest. While Paar started many traditions during his time with The Tonight Show, insulting other guests thankfully never caught on.