I think a lot of teachers assume that people in other jobs gets breaks and lunch and can go to the toilet when they like. That's not true of many jobs - I often will eat my lunch at 6pm because it's the first chance I've had all day, and I'm sure I'm not alone.
Teachers also sometimes think they are the only ones that work with an audience, and are 'on display' and on their feet all the time. Again, not true.
And many of us work evenings and weekends for no additional pay, for no more money than teachers get, and a fraction of the holidays.
I have family in teaching, and close friends in teaching. I've lost count on the times my teacher friends have gone out without me in an evening, because I'm still working. Many work very hard and very long hours, but some are very successful with less. Yes its tiring, but no more so than many other jobs.they don't have the monopoly on tiredness.
Personally, when I've done teaching (of adults or children), I found the prep quite intensive, but the actual teaching not very stressful at all.
I do talk for a living though, so an audience doesnt phase me.