When I was about 17 (I'm 29 now) I worked at a small dry cleaners inside a grocery store.
I usually worked Saturday open until close 9-5, my dad decided to bring me my lunch but I happened to be serving a customer so my dad just waited. This man was picking up clothes obviously, I can't remember exactly what was wrong as it was so long ago but he didn't like how something was cleaned maybe.
I'm trying to explain to him that I can send it back to the actual place they clean it but it won't be ready until Monday, he didn't like that and he started getting angry and raising his voice.
I kept eyeing my dad and I could see he wasn't impressed now obviously this customer didn't know he was my dad and noticed him and told him to go ahead, my dad says in a stern voice "that's actually my daughter".
As soon as my dad said that, the customers face dropped and instantly said to me "I'll come back on Monday" and left.
Who knows if my dad wasn't there, he could've kept yelling at me and there was literally nothing I could do!