People have remarked how weird it was that David Letterman's confession that he'd had extramarital affairs with staffers elicited laughs and even cheers from audience members. Some speculate it's because the audience must have thought he was joking when telling them about the extortion attempt against him. Others thought that maybe people laughed because — hey, it's David Letterman, so anything goes. Some wiseacre decided to show how weird it really was by adding a laugh track to Mark Sanford's confession he had an Argentinean lover. . .