But it is a lot of work.
I can see how you could be a crappy teacher and get by. Boring textbook lessons every day. Don't change things up or be creative. And you could leave at the bell!
But I would hate that. I'm always changing things up, experimenting with new labs, inventing new games, and scouring the internet for interesting videos and funny science cartoons. And as a result my classes fly by and we all have fun. Case in point today, I had a room full of teenaged boys with words taped to their foreheads walking around and playing a version of the game "Headbands" to review for their exam. And they were having a great time and completely into it.
Anyway, the more I keep planning and innovating (the stuff I like), the farther behind I get in the drudge work of marking, photocopying, cleaning up my lab, and other things I hate. And then I feel stressed and ugh, and it's an awful cycle. I often stay at school way too late trying to get caught up but I'm not even that productive because I distract myself either by planning something new, or get caught up chit-chatting in the staff room.
This year I'm trying to leave school early more often and it's great! I leave, go to the gym or run errands and come home refreshed enough to maybe to a little bit of school catch-up. I must keep doing this.
Yesterday, I left early to go on a three-hour expedition to get supplies for a long-term lab for my grade 12 biology students (they have to take another semester of bio but with another teacher). It was still work-related, but being out of the building was so much better and I had fun because a friend was kind enough to join me.
I need to get out of there early more often. I must continue this into next semester despite the spectre of another new course to teach for the third semester in a row. I'm no longer using "I'm teaching a new course" to allow the rest of my life to fall apart.
January... so far, so good.