Watch: The ’Full House’ guys help Jimmy Fallon with his nightmares

Fallon describes the evolution of his six-season run on Saturday Night Live,from 1998 to 2004, like this: “First I did impressions. Then I wanted to do characters. Then I got to do ‘Weekend Update’ with Tina Fey, which was the greatest. Then I became the guy who laughed in sketches. Then I left.”