As a counterpoint, I date a lot of school teachers in NYC. Almost every one of them has the same story... They were working in another job with crazy hours, like film production or advertising, and specifically became a school teacher because it had easier hours, good benefits, and summers off.

Perhaps compared to doing nothing, 7:30 to 6 is a hardship, but if you're coming from a normal NYC office job where it's not uncommon to work 9am-10pm it sounds like a vacation. Also, you don't actually have to be at the school from 7:30 to 6. You typically can go home by 3:30 and do whatever grading you need to at home.

On the other hand, being stuck in a room for 8 hours with NYC teenagers sounds like one of the most exhausting and frustrating tasks in the world. Maybe all that down time is necessary for recovery? I certainly would (and do) choose 10 hours a day futzing with C++ over 8 hours a day with teenagers who don't want to be there. Would be nice to have summers off, though.