Your last paragraph is key - once you establish boundaries for yourself, you're free to be generous and kind because you are clear with yourself on what's Ok and what's abusive.

Once you have that, the other factors (industry, city) don't matter - you are able to act the way you want independently of how people are, because you're confident that you won't let their transgressions cross over into "you."

It's been a long process learning this for myself as well.