Why does a comedy skit become even funnier when one of the comedians starts to lose it and begins to laugh? I just watched the classic Will Ferrell SNL Cowbell Skit with Christopher Walkin, and found that it was Jimmy Fallon, trying desperately to swallow his laughter in the background, that amused me the most. At one point Fallon actually started chewing on his drumstick in an attempt to mask his loss of composure, and man, I was dying.

It’s like their cracking up and ruining their own suspension of disbelief just kicks the comedy up to 11. Why is that?