Yeah, teaching is REAL easy to get burned out on, especially with the shitty pay and hours, and the constant stress in the first few years especially. The non-monetary rewards are great, of course, but DAMN there's a lot of crap you have to do that has nothing to do with teaching, and takes up all your time, never getting enough sleep or any social life... required committees, supervising detentions, coaching this or that club, department meetings, staff meetings, state-mandated testing, going on strike (unions), calling parents, getting bitched out by parents, catching cheaters... oh man. Do all of you REALLY want to get into that, with teaching as the ideal job? It's not like Dead Poets Society, y'know.
All that said, I deeply admire shesus for going back to the profession after leaving it... that takes guts. I'm don't have the motivation or passion that I would need to go back anytime soon.