“Friends have suggested that I am the least qualified person to talk about happiness, because I am often down, and sometimes profoundly depressed. But I think that's where my qualification comes from. Because to know happiness, it helps to know unhappiness.”
Source : "George Clooney Says He “Destroyed” The Role Of Batman, Weighs In On Ben Affleck’s Casting" by Kevin Jagernauth, www.indiewire.com. September 27, 2013.