I left high school teaching because the job was intellectually stultifying and I really don't like the direction public education is going in. I also feel like the profession is given little to no respect from most quarters these days--students, parents, administrators, and in terms of pay.
I also found that your bosses, the administrators, tended to be people who weren't very good at teaching, so they left the classroom to do admin.
Also, I would just make really really really sure that it is the right fit. If you don't have the right personality for it and if you don't truly enjoy it, you will be that miserable burnt-out teacher that we all hated.