When Mel Gibson took a seat across from Jay Leno last night to shill for his revenge flick Edge of Darkness, the time seemed right for Leno to ask a 2010 version of “What the hell were you thinking.†Gibson, as you may recall, has been relatively absent from Hollywood since his notorious anti-Semitic rant in 2006. Leno didn’t probe, but we were reminded of the incident when he asked Gibson how it felt to be back from his self-imposed hiatus. Gibson’s answer: “What made me quit in the first place was that I just felt bored and kind of stale.†So that’s what it was. We thought it was something else entirely.