I've worked in both secondary and primary education and I've seen the expectations from teachers increase to an unsustainable point.
Apart from the huge responsibility, I wonder if non-teachers are aware of what the working day is like for most teachers? It came as a surprise to my husband (not a teacher) that you don't get breaks/lunchtimes as such - you will be on a duty or running a club nearly every time. You so-called 'frees' will be spent covering lessons. You need to get there well before the children ( 7.30 am) and of course, can only start your admin (planning, meetings, marking etc) when they've all gone home so you often work well into the evening and at weekends. I've had so many remarks about teachers knocking off at 3.30 etc.....groan.
So many things make teaching a much more stressful job than it was a generation ago - or even a decade ago, from what I hear. Behaviour has worsened for all kinds of societal reasons, while sanctions have decreased. The attitude of both students and parents to teachers has become disrespectful and unsupportive in many cases.
I used to compare it to being an actor. You go 'on' first thing in the morning and boy, you'd better know your lines and have all your props in place. Unlike most jobs, there won't be any downtime where you can go to the water-cooler, take 2 mins to chat to a colleague, get a cup of coffee or even go the loo when you need to.
Yes, I know many jobs are stressful but the scrutinised performance aspect of teaching and the relentless pressure of the school day make it very tough to sustain in a way it wasn't 30/40 years ago. As pps have said - if it was easy there'd be people lining up to do it. It looks easy only to those who've never tried it, or who have very little imagination!