Dear Kids in my class,

I think I have mentally checked out and don't have the patience lately for a lot of the things teaching involves. This leads to me being annoyed by 90% of the things you guys do throughout the day (as opposed to the usual 50%).

But my angry face looks a lot like my not-angry face. (And my stern voice sounds a little bit more like I'm 10 years old instead of 7.) So you probably haven't even noticed.

Sorry anyway,
r

P.S. To be fair though, I think you guys have also doubled your annoyance factor in the past couple weeks, haven't you?