As lovers of gossip, there's one question that we all want to know when it comes to Saturday Night Live, and that's which musical guest or host was hardest to work with. "Everybody wants to know worsts," former Saturday Night Live cast member and Barry star Bill Hader said in response to a fan's question on What What Happens Live with Andy Cohen Thursday night. He was there alongside former castmate Jay Pharoah, and despite their initial reluctance, the two agreed on the hardest celebrity to work with: Justin Bieber