Used to work in a bar/nightclub and got all sorts:
A woman once complained that she didn’t like the colour of the sofas in the lounge bit. She was completely sober by the way.
A man once complained that I hadn’t warned him that Strongbow was cider and not beer.
Another man kicked off when we only had the beer he wanted in bottle form, and not on draught.
A girl (young in fairness) was eyeing the shelf of liqueurs we had behind the bar. We rarely sold much of them as we didn’t do cocktails and customers didn’t tend to order a liqueur as their main drink unless it’s something like kahlua, or occasionally mix one with lemonade etc. She asked me about them and what they were so I told her they were liqueurs, normally used in cocktails and were often 20-25% proof etc.
She asked for a blue curacao with ice. I told her it wasn’t really a drink people ordered straight as it was normally part of a cocktail but she insisted. So I poured the standard measure and gave it to her over ice.
Anyway she went mad. Saying how tiny the amount id given her was and I was mugging her off and ripping her off. I tried to explain that liqueurs are served as standard 25-35ml and just was a normal measure but she wasn’t having it. She said she expected at least half a glass. Eventually after much kicking off my manager was able to make her understand that blue curacao was served in that measure in bars, and wasn’t just poured to the top like a WKD.
I know when you’re young and new to bar/clubbing you might not know what’s what with drinks yet, but doesn’t mean the bar staff are actively trying to rip you of!