I've never understood this notion of taking someone elses' job - one which you actually know nothing about - and judging whether they're either working hard, or 'know the meaning of stress'. It implies that you're not happy in your own job, doesn't it? Okay, well if you're so amazing that you feel empowered to judge everyone else - then go and get yourself an easier job.
There's different levels of stress and expectation in every job, be it the deliverables or the people you work with. Also, some people simply don't know how to plan their time properly, so end up stressing themselves out, when actually there's no need. Usually, that's when I often hear these ridiculous judgements made on other people.
I've had it myself too, in the past. I never look stressed, because I regimentally plan my work and I have rules for taking anything on. I've had colleagues in the past comment that I look like I'm not doing anything and obviously overpaid - and yet, in meetings, these are the people who - unlike myself - could never give definitive answers or reasons as to why there was slippage on a deliverable. Less time spent on worrying about others, and you'd do a better job yourself.
I think teachers do a great job and, personally, I wouldn't do it for all the silver in the world. If all you can criticise - because, some people just love to criticise - is that they get long holidays, then - well - it isn't much is it really? They're teaching the next generation; the generation that will, one day, succeed you and drive the economy and yet, naively, all you can do is criticise them?
If you hate your jobs people, go and get what you perceive to be better, or easier ones. Personally, I love a challenge and I thrive on stress - brings out the best in me; so, would I want a cushy, boring, monotonous job? No fudging way.