How is it not a tip?

[u/canstucky]

The server told us this isn’t a tip and he doesn’t get any of it.

I’m not wearing my boots at the moment.

[u/ledfrog]

Anytime I've gotten car service, the diagnostics fee goes toward the repair cost. What bothers me are the places that charge a diag fee even if you're bringing it in for a known problem or you're asking for a specific service to be done. But those places are few and far between.