I bartended for a long time. I had 30 stools and If I didn’t like you basically no longer existed or I’d cut you off. You never piss off your bartender. Servers don’t have the same power. They work for $2.30 + tips. They typically have maybe 3-7 tables each and they are at the mercy of the patron. Tipping culture leads to a sense of something more being owed. I’ve seen patrons ask for things from a busy server simply because the server has too. It’s rather disgusting when you see it happen. On top of the abuse most servers are taxed on a percentage of sales so they are taxed. If they are stiffed on the tip they may still pay taxes on an assumed percentage.