"Teacher Man" by Frank McCourt

So, what took you so long?
I was teaching, that's what took me so long. Not in college or university, where you have all the time in the world for writing and other diversions, but in four different New York City public high schools. ( I have read novels about the lives of university professores where they seemed to be so busy with adultery and academic in-fighting you wonder where they found time to squeeze in a little teaching.) When you teach five high school classes a day, five days a week, you're not inclined to go home to clear your head and fashion deathless prose. After a day of five classes your head is filled with the clamor of the classroom.