I think this is a HUGE generalisation CQ!! Its not the norm in many countries - as Middlemarch said its not in Greece, nor in Hungary or Iceland (in fact they get quite offended if you try to tip for lots of things) and from what I remember when we went nor was Korea and Dubai. Each country is very different - if you can try to research before you go - the lonely planet/rough guides are usually good at this. Otherwise just do what you feel comfortable with. Tipping for everything has always been a bigger part of life in America because it really does make up a huge part of their wages (unlike in UK and other countries).