We always tip 10% of the total price whether the service is good or bad. Occasionally, I’d get an unnecessary smart comment about something or other, then No Tip from Ol’ Lep.
We were in a Chinese restaurant in Boston some years ago and I left my usual 10% tip. A member of staff followed us out to the street informing us the expected tip was 12.5% and he wanted the difference, I coughed up, but thought his actions somewhat weird.
In Ireland I understand the sharing of tips is covered by law. If any member of staff has a grievance then there is a legal route. I bet some trade unions could represent their members along this route.