In my experience it is fatigue first and failure of the teacher to keep the time limit second.
hmmm, I used to like to go 2nd back then. The first one might have (mostly) "technical difficulties" that get solved afterwards.
The latter you go, the more desperate the group will become. Fatigue and whatnot.
Agreed, I like to go in the first ~20% but not actually first. That gives you a chance to quickly make any changes from good qualities you noticed in the first ones, but get it done before fatigue sets in. And it's just nice to have it out of the way so you don't have to stress!