Justin Bieber (June 21, 2012)
As Letterman got older, his profound lack of interest in youth culture became more and more obvious. Take, for example, this interview with Justin Bieber, which starts off pleasantly enough. But as it rolls along, the host's clear indifference to the Canadian phenom creates a noticeable, entertaining tension. By the time the Beeb incorrectly refers to Michelangelo's Vatican painting as the Sixteenth Chapel, well, there's no stopping Dave from mocking the poor kid. Bieber tries to smile his way through the chat, but when he finally tells Letterman that he feels uncomfortable, the host cackles and delivers a comeback that could be the master's mantra: "That's what I do: I make people feel uncomfortable."