In Spanish you could just say Usted (you; a type of speech), it's already formal. No extra need for sir or ma'am if you don't want to.
In English I don't really use sir/ma'am, I do use please and thank you.
I always greet my friends' parents and I would like all my friends to greet mine. You don't have to kiss ass just say Hello/Good day.
When it comes to eating, that's when it's dodgy

on top of being a lefty, I'm clumsy
