Weird that when I'm in the staffroom marking, the teachers who interrupt with a million and one little, niggling, problems for me to solve abruptly drops to one, prefaced by an apology.
If I have a heavy markload, I feel entirely justified in explaining I have a deadline to meet - can it wait?

Yet, if I'm reading - you know, reading, the meat and two veg, the nuts and bolts, the heart of the darkness, the raison d'etre of being an English teacher, the glistening centre - if I'm reading, I feel somehow I couldn't possibly shoo them away with a "sorry - I'm busy. I'm reading."