If you watch The Office [1] regularly, then "that's what she said" needs no introduction. Michael — the big boss ("that's what she said") — drops the phrase as much as possible to add a bit of innuendo to all office banter and prove that he's got it goin' on ("that's what she said") in the humor department. It eventually became contagious and everyone now drops the joke. They can't help themselves. It just keeps popping up ("that's what she said") . . .