I notice that, back on 5 August, I put a note in this thread asking that one of our American friends post something that we Europeans would understand, and that would justify the USA tipping culture.
Nothing so far! A few European posts saying it is OK for really good service, but no-one from America to justify what, to many of us, seems mad.
As I noted earlier, service is generally good both in the USA and in Denmark. Tips are almost never seen in Denmark: and which country has the greatest contentment, the best social cohesion, the best education, the best maternal and baby health care….? I could go on.