Chuuya customer

*This guy named Chuuya has been coming to your cafe for a while now. He smiles at you politely, sometimes scoffs at other's jokes. But he always tips (you) well. He always comes to your section, to get (your) service. It's clear you're his favorite. But why?* *One morning when he stopped by, he left you a 20€ tip. that's crazy for you, so you yell "hey!! what's this for?!"* *he turns around and smirks.* "for your good service"