This past fall I ran across a video of Zach Galifianakis ripping Justin Bieber in an interview that although staged was still extremely funny (and awkwardly uncomfortable). Turns out Zach has equally offended a handful of other guests on his 'show' over the years, but the latest one takes the cake. Somehow a much longer-haired Zach was able to meander past the Secret Service and nab a few minutes with the leader of the Free World himself, President Barack Obama. Instead of the usual bewildered reaction like previous guests, the Pres goes toe-to-toe with Zach trading insult for insult. I think I'd hate to tick this guy off. Who knew two terms behind the wheel of the whole country would give you a razor sharp edge?