[masterzora]

To an extent, at least, it's not so ridiculous as your "logical conclusion", at least not based on current US tipping etiquette.

For one, 10% on $15786 is a little silly, sure. But current etiquette already recommends flat rates for certain types of services so this could logically be extended to certain other cases.

And secondly, even brought to the logical conclusion, extending tipping would only make sense where it could reinforce proper incentives and would be actively bad where it reinforces perverse incentives. A legal avenue for bribing cops is certainly problematic in a way that bribing waiters for better service isn't, for example.

That's not to say I'm arguing in favour of tipping but I don't think it's as clearly unreasonably as your example would suggest.

[maxxxxx]

In what way is a waiter's service different from a supermarket cashier's service or your dentist's service? All I am saying it's totally arbitrary that among many service professions only for waiters tipping is an essential part of their income. Sure you can tip your plumber but even without tip he will earn good money.

[masterzora]

Where did I--or anyone--say it was different? Again, we're talking abstract, not current status quo.

That said, there are key differences between a dentist or plumber and a waiter or cashier. The obvious one is a private-practice dentist or self-employed plumber where they're setting their own fee and getting directly paid. In such cases there's no problem for tipping to solve. The other big one regardless of public or private is that there's a major power imbalance where the dentist or plumber is effectively acting as the agent of the patient or customer. Check-ups, routine cleanings, and such aren't an issue but when it comes to things that need fixing it's the dentist or plumber telling the customer "this is the service you require" and selling them that service. This is a principal-agent problem itself and tipping only exacerbates the issue rather than solving it.

Like I said previously, the logic of where tipping could or could not make sense is based on what sort of incentives it reinforces, if any. And, also like I said previously, I am not arguing in favour of tipping, either, and I'm especially not arguing in favour of tipping making up an essential part of one's income.