I did the jobs you described part time while I was studying. Yes the jobs you listed are more physical, but you gain a flexible schedule and the chance to combine it with different things, art, writing studying etc.
I remember a conversation with a barber. I told her I was a programmer, she immediately reacted with, "I would never be able to do that, I need to do something more creative and social". That was a bit shortsighted from her side. But it also gave me a bit of insight that not everyone wants to sit in an office all day. People are really different, some might do it because they cannot do anything else. Other probably talk about you as you are talking about them right now.
Finally, remember that not all countries have the same social/tax system. I'm not sure where you are from, but when your coin is very strong versus the country you are visiting, it is already very skewed. Next to that countries like the US you get allot more "liquid" money. Money you can easily spend. Some countries actually tax more, giving you a more stable foundation, but it will mean you have less money after taxes.
Just treat everyone like they are human.