spoilers:end of spoilers
I can think of a couple of incidents where he was a bit irrational and showed some temper. During Legionquest when he gets in an argument with Cable - though he outright tells Rogue he feels stupid about losing his cool later. During his tussle with Joseph after X-Men 45 but pre-Trial of Gambit when they fight over Joseph hanging out by Rogue's window. That was all around stupid. And when he storms off after Xavier is being unreasonable and overtraining them. There's also the time on Utopia while he's still having trouble with the Death persona, where he freaks out on Cyclops for sending Rogue out alone. But yeah, notably none of these were against humans. In fact, he's very restrained in X-Men #45 in the bar scene when he's tracking down Rogue and Iceman and the humans are threatening them and acting like bigots.