The most frustrating thing has been the tip prompt that happens before service has been rendered. A tip is based on service. If you haven't received the service yet, the fuck is the tip meant to reflect? That you succeeded at breathing?
I have a diametrically opposed take. I prefer tipping before.
It's my way of giving someone a little appreciation because they're (typically) doing a job I wouldn't want to do myself.
It's got virtually nothing to do with the quality of service I get. I always tip the same amount even when service is bad. There have only been maybe 3 exceptions in my nearly 3 decades of adult life.
I'm fortunate to be able to afford a little bit of generosity for service people, so I do it.
Edit: I should add that, in places where there's a customary tipping practice (eg: US restaurants), I tip above the customary amount no questions asked. The "generosity" is the amount above customary.