Originally Posted by PaulRO

In my observation of 109 nations, and how many more cultures?, the overall rule seems to be either:
1. if in a culture where courtesy, kindness, friendliness, appreciation, praise, correct behaviour, no loud voices, no brashness and suchlike are the local rule, then a tip is not part of the equation, and is often seen as an offence, while being welcome elsewhere.
2. if in an economy where such issues are not valued, you'll get mashed up or socially excluded if you don't tip, and then properly.

I haven't been around very much, but some might recognise my slight tendency to associate the USA with option 2. Could be wrong.

BTW: any reader who feels s/he has benefitted from this comment, please deposit 23.4% of your benefit on an account of my choice. Max 10k, otherwise I shall blush.