Pedrocut
Master Barmmie
A funny story I heard about speaking the language, a young guy trying to impress his Spanish girlfriend's father by saying, in Spanish how important he was, caused a stunned silence, what he'd actually done was tell the man he was impotent.
It can work the other way. When in Portugal and faced with young ladies trying to push a destination or restaurant, I use the impersonal “you.” After been taking back a bit they laugh and I can have a good conversation until the wife drags me away!