I think any student with an over-zealous mother can be caught falling asleep in class. My friend used to teach a grade 6 girl in her home at night until 11 or 12. When she left the house, the rest of the family was already in bed, except the 12 year old! She need to get into a good middle school...
As for my preferences, I like teaching the elementary kids because they are so fun to be with. My very best class ever was a group of 10-11 year olds whose level was high enough to be conversational. We could discuss things, and play games and it was all good fun. Once they turn 13 or so, as the enthusiasm begins to lose out to self-consciousness, my interest begins to wane as well. Plus it's not longer funny if I act like a goof.
