Yeah this is definitely a thing. Also how people talk/interact with checkout or bar staff gives you a big clue too. Not necessarily whether theyāre rude or not but just the manner of the interaction. Canāt really explain it properly.
The real tell is if they put washed glasses at the back of the cupboard. Not everyone would do this obviously but if they do youāre damned right theyāre a bar veteran, probably who still have nightmares about it.
you can tell people havenāt been a waiter if when the waiter comes with the food they start moving stuff around on the table, like trying to help but just doing it all wrong and making it more difficult. also after the meal handing plates to the waiter when theyāre obviously trying to collect things in a certain order to be most efficient.
Iām not one for broad brushstrokes but I donāt think I trust anyone who hasnāt had at least one low level job in retail or hospitality (obvious caveats implied)
Iāve never worked in a bar but I once responded to a drink spillage by nipping over to the bar and asking to borrow their blue roll and felt a weird kind of smugness when one of the staff asked if I worked in a pub and how I could possibly know about blue roll it I wasnāt a bar person.
A lot of this is applicable to retail/service work in general though, the assumption that the people serving you are human beings who are likely having a busy/miserable time, the instinct to solve or prevent mess from happening, not waiting for the staff to solve all your problems for you, etcā¦