In most other rich countries the waiters and other service staff are paid good enough, not having to rely upon tips for a living wage.
PS> In some countries a “service charge” may be added to you bill, though.
There may be a “tips jar/box” placed on a desk near the exit, or cashier counter, where customers may drop in a few coins (or bills) to show their gratitude for exceptional good service. Tips collected are sheared by the staff.
Here is a guide to Tipping in Europe:
Only in America is tipping “compulsory”: