This is why I dropped out of teaching (and this was nine years ago now):
Inclusion policies - not having children with additional needs in my class, that was fine. It was that I was expected to teach them with no support and no extra training. I felt I was failing everyone - them and the other children in the class.
Deteriorating behaviour - I felt that having to tackle that alongside increasing academic targets was actually impossible
As a teacher, I NEVER went home of an evening with that satisfied "Ah, I've done everything" feeling. Even if you worked 25 hours a day, you would NEVER finish everything you were supposed to do on paper. You wouldn't believe how bad that is for morale.
I found something else I wanted to do more. So many teachers want to leave teaching but they have been conditioned to think "What else could I do? I can't do anything else" which is simply not true. I wanted to get out before I lost all my confidence and was just one of those bitter, moaning teachers.
Yes, as teacher you are expecting to be a social worker, a parent, an accountant, a counsellor, as well as "an outstanding classroom practitioner" . I knew I wasn't cut out for some of those things, no matter how good I was at getting children good results in their SATs.
Finally I wanted a bit of spare time. I didn't have any at all.