Five times Louis C.K. got really philosophical on late-night talk shows

Lots of people like Louis C.K. for his stand-up comedy or TV show -- but thanks to some of his brilliant rants on late-night talk shows, he's also become something of a viral video sensation. Even people who have never heard of his FX show, "Louie" (which returns after a nearly two-year hiatus on Monday night) have likely seen about a million links to his "Everything's amazing and nobody's happy" YouTube video.