I live in Germany and German queue etiquette throws me off all the time.
It appears similar to British queue etiquette, just to lull you into a false sense of security, but it is quite different right at crunch point which really makes me anxious.
Sometimes you have long lines, but at other times people wait in a kind of crowd of no particular order, and whoever is near the front and quick to respond to a server calling out next is next. And nobody seems to mind who got there first.
At supermarkets of course you queue at the checkout. But if somebody has only two or three items it's expected that you let them go first. This is fine, but you often get several people doing it at once which irks me. If a new checkout opens up you can launch yourself from the back of a queue and land right at the start of this new one and everybody just accepts that that is the right and proper way.
Sometimes two queues for two tills will form in smaller shops, like Woolworths, (they have Woolworth's here, it is thrilling, but mostly full of junk, huge displays of ashtrays and all of those rejected home decoration signs where the English is botched.) but then people don't behave consistently when an opening comes up, and it makes me feel really, really anxious.
It's weird how these things are ingrained.