48. Crispin Glover Pushed Him Too Far
If you're going to dish it out, you've got to be able to take it in return. On one of the most infamous episodes of Late Night ever, Crispin Glover appeared in-character while promoting a movie. Anyone who's seen Back to the Future knows Crispin Glover's a bit of a weird guy, and Letterman was clearly unprepared for his bizarre antics. Eventually, Glover kicked within inches of Letterman's face, and the host had had enough.
Letterman just walked off the set of his own show right then and there. Safe to say, it wasn't his finest moment—but it got a whole lot worse than that.
49. He Nearly Suffocated Richard Simmons
Maybe one of Letterman's most infamous feuds was with fitness guru Richard Simmons. Simmons appeared on Late Night and Late Show all the time, and the pair seemed to have a pretty close relationship—but that all crashed and burned after an appearance in 2000. Simmons was dressed as a turkey (just roll with it) and Letterman sprayed him in the face with a fire extinguisher (just roll with it).
Unfortunately, the results were disastrous.
Simmons suffers from severe asthma, and the blast from the fire extinguisher resulted in a brutal asthma attack. Letterman made light of the incident, and Simmons was furious. He didn't come back on the show for over six years afterward.
