Heinrich Lübke (a german politician) to the english queen in the 60s:
"You can say you to me!"
What you have to know: In german there are two words for "you". You can say "du" or "sie". "du" is for people you know very good (friends, family etc). "sie" is for strangers you dont know (strange people of the street, people at work etc).
If you know strage persons a bit better you can offer them to say "du" instead of "sie". Its a bit more personal.