Family Guy

"Sie" vs. "du" if I just started off with informal chat say in a hotel reception, bar, restaurant etc – would anyone be offended?

Hi there! Next month I have to visit Cologne and spend there about one month because of my job. My German is not really perfect, sad but true! I'd like to know, if it's easy to use there public transport and if I can buy ticket like oyster card in London? thank u!

just came back from Berlin, the city is full with nutella-banners like this.

I find it amazing ^_^ , isn't it?