Some random things to ponder...
German doorknobs are never the round kind you twist like in the US. They always have a handle you push down.
German showerheads are always vertically adjustable, not like the permanently mounted kind you usually find in the US.
Sidewalks are made out of interlocking bricks, never concrete slabs.
It's illegal to turn right on red.
There are no four-way stops. Usually there are traffic circles instead.
Grocery stores are not open on Sundays. Nothing is.
Most things I don't even notice anymore, because they seem normal to me. But I will try to continue this list.