Boys would be boys. Maybe Jack had changed, but John hadn't. Wouldn't. When the man had enough liquor in him (and in this case, no real desire to pay up or tender to do it in the first place) a fight was inevitable. It used to be a rush. If he was honest, it was probably what had brought them together in the most carnal of ways all those years ago. So when his stool was shoved and the blend of gravity and being startled had it tumbling backward, John barely managed to catch himself against another member of the clientele and by one hand on the bar, which had sent a number of drinks flying and glasses rolling to crash on the floor.
"Well, if that's how you wanted it, all you had to do was ask," John strained as he squirmed to his feet and kicked the tipped stool out of the way, then violently batted a full shot glass at Jack and took a swing with his other arm. He wasn't a noble fighter, he was a cheat and a bastard. He'd stab a man in the back for the hell of it, sucker punching Jack was nothing.