The problem is not poor service with minimum pay. The problem is customers happy to lower expectations while companies expect more for less. Paying people from 8:30 but expecting them there 15 minutes early and then the same at the end. Or paying everyone till 8pm and the store closing at 8pm but then there being jobs that need to be done before you can go.
And if your reply to this is “don’t do that job then or refuse or walk out at that time” then you are not living in the real world. AIBU to believe every worker should be in a union so that they can have a collective voice and not be exploited by customers, managers and company owners.
Anything that people have an issue with “little extras” is told about good will. These managers etc, don’t expect goodwill to be reciprocal.