[_delirium]

That was traditionally the view in parts of Europe as well, although nowadays many people will be happy to accept a tip, especially since there are so many foreign tourists willing to offer one. Some people used to perceive it as an implication that you were in need of charity, i.e. that the reason you'd offer a tip to a waiter but not to an architect for rendering good service is that you didn't respect the waiter as a professional in the same sense that you respected the architect.

Sometimes it's contextual, e.g. in Greece the traditional norms were that tipping young people working at a restaurant as employees was fine, but tipping an owner-operator of a family-run restaurant could offend them, being taken as an implication that you thought they couldn't manage as an independent businessman, and needed a gift. Instead if you particularly liked their service, the socially acceptable way to show it was to either order more things, or return for another meal later; that way you gave them more money but in the form of more business, rather than an outright gift. (Nowadays this is only really an issue if you're Greek, especially a Greek from the same town, where tips, especially large ones, might be taken as having some kind of odd social implication. If you're a foreigner, tips aren't going to offend anyone, and are perceived basically the way North Americans would expect, as a thank-you for particularly good service.)