When I was in Edmonton last, anger ‘came upon me’, as the Tibetans like to put it. This is how it happened. I wrote later to a friend; this is the edited version.

At around 03:15 in the morning, about -25C outside, and perhaps not the best start to a teaching weekend, a young man kept banging on the outside fire door; this went on and on until I woke up. I opened my door and saw this face in the approximately 300 x 300mm reinforced glass opening in the door, about 10m down the corridor.
I let him I’m; he was yelling about being locked out of his room for half an hour; I did not think to ask him his room number or where his key was, or what he was doing on the fire escape, and (this is the surprise) I was so annoyed at being woken up I grabbed the front of his jacket, said, “you woke me up” and shook him (like push-pull; not quite punching, but then like that while not letting go; I am pretty strong, as you know; he shook like a rag doll. In any case, it was over over in a few seconds; and honestly, I can’t remember more detail than that). He was quite a bit taller than me, but none of that matters in the moment. 
So, wide awake by then. I was so annoyed I could not talk to him. He was annoyed that I shook him, and he stalked off complaining.
I went back to bed and, amazingly, was able to sleep within a half hour.
Why was I reminded of this?  The night before last I was awoken by loud young men; I opened my door to see the last of them in the doorway, looking back at me. “Keep the noise down!” I yelled at him; he was large, in a football top, and surprised. I gave him the #2 look, and held his gaze for 20″ or so; he turned and went into his room.
Back to sleep.