One thing you can do in Germany but can't in the US is "drinking in public". Bring your beer, sit down at the market, park or just walk around while drinking it.

A very common thing, specially in cities with a high amount of students or the like is the so called "Wegbier" (on-the-way-beer) where you go with friends from your house to i.e. a pub and on that way you have a beer to bridge the gap so to say.

I got stopped for this in Lithuania and Canada and basically learned the hard way that this is not common elsewhere.