I was a server for years and I don’t know what political views my customers had directly, but my absolute favorite people to serve were tradesmen with their families (at least locally, tradesmen are often assumed to be conservative). They tended to be pretty relaxed and tip well. Those are historically union jobs, and I don’t know if the people working them still vote in favor of worker solidarity, but they still culturally support it, ime.

My least favorite people were also people who are often assumed to be conservative, for what it’s worth: families on their way home from church. They were nitpicky, required a lot of attention, and tipped like shit, plus they often tried to get things comped off their bills by complaining about something on their way out.