Maybe it still can. "I really enjoyed doing those," Leno says of his appearances on Letterman's NBC show, during a time when many of the old-guard talk shows were winding down and new blood was being recruited to take their place. "It was the first time that the host and the guest, for me, were the same age. When you're on with Johnny [Carson], or Merv Griffin, or even Mike Douglas, there was a certain reverential attitude you had to have. … Being with Dave, my natural inclination was always to be the smartass.