Grading exam papers

Some time ago I made the (probably stupid) decision to grade all of my students' exam papers, to give me an idea about how badly I failed as a lecturer. Gah. Of course, it does not help with my general mood that I've been up from five am doing this. Anyway, I've been trying to keep myself fed and watered and coffeed and I'm taking frequent (painful - remember, yesterday's marathon?) walks around the department to try to calm myself down. But what really helps is this: