30 years of teaching

Came to an interesting conclusion today.
I the first years of teaching I spent all the time thinking about what I would say next.
After 10 years I started to think more about what the students were thinking.
after 20 years I knew what the students were thinking.
After 30 years I know what the students are thinking but sometimes don't know what I just said and occasionally write something random. I amuse myself by asking questions knowing the wrong answer students are going to give so that I can show them why the right answer is right and theirs is wrong.
Its a fun game.