Video Evidence: Drew Barrymore, 1995
In her younger days, Drew Barrymore was a real free spirit. During a 1995 Late Show appearance, she told the audience where to see nude performance art, discussed Steven Spielberg's thoughts on her Playboy spread, and flashed Letterman during an impromptu dance.
All good, right? Apparently Barrymore doesn't think so. When she returned to Letterman's couch in 2007, Dave took the opportunity to remind her of the old days. She replied, "Turning 32, I think I'm not a different person 'cause I'm certainly, you know, as wild and free-spirited as ever, but I'm just really glad I had that opportunity and got that out of my system." Letterman was bummed.