I am not being sarcastic with this comment: I find the Germans to be very calm people. Really! I am actually surprised they went to war... The Germans don't get angry - or, at least, the northen Germans don't get angry.
If someone cuts in line in front of them, they politely ask WTF, and request that the person go to the back of the line. They don't get angry.
If some service does not work properly (internet or telephone, for instance), they politely call the appropriate company and request that the problem be resolved. Now, Customer Service in Germany is nowhere as awesome as it is in the US, but it works. The problem gets solved (or it doesn't), and they don't get angry.
If something they buy does not function properly, they go back to the store and politely request a replacement. They get their replacement, and they don't get angry.
If someone is playing music too high, they politely ring the bell and ask the person to lower the volume. The person actually lowers the volume, and neither of them get angry.
If someone is being too obnoxious, they politely ask them to quit the crap. They don't get angry.
The Germans are direct, and they don't beat around the bush. They say what they think, when they think it. And although you might think their language sounds harsh, once you learn it, it actually sounds nice and smooth. The Germans are clear in expressing their feelings, good or bad, and they express them to you, in your face, if they concern you. So maybe some people think they "get angry" - but no. They are perfectly calm and relaxed. They just want what they want, and they want it now. They are, however, capable of requesting their wish politely.
Don't mess with a German on a bicycle. Having been through Honey getting his drivers' license in Germany, I can tell you that the Germans emphasize bicycle awareness. It's like the bike has priority even over pedestrians. Sometimes drivers are not all too careful... and some come really close to hitting ciclists, but ciclists also usually overreact, they scream stuff that I am not taught in the most advanced of German Language Courses, things that I can only assume have to do with moms' professions, and feces and excrements, and words that describe profane sexual acts... they get angry. They scream and yell, other pedestrians also yell at the driver - dude, they get pissed! And the truth is nothing happened. Yes, something could have happened, but nothing actually happened. But if you want to see a German angry, mess with them while they are on a bike.
To be honest, the Germans only get really annoyed when they are "attacked" while on their bikes. They get upset. Thet get mad. They become unhappy.
You see a real angry German, a 100%-out-of-their-senses-German, a real needs-some-kind-of-medication-German, a real how-the-heck-can-someone-get-so-angry-German, a real OMG-I-don't-want-to-be-here-German when...
...you drive "at speed limit" in the "unlimited speed" part of the Autobahn. There is something you need to understand: the Autobahn is no different from any other highway in your country. In fact, sometimes they are quite small and unimpressive. Sometimes - most of the time - they have only two lanes (the driving lane and the passing lane). And most of the time they do have a speed limit. The limit, however, is 120 km/h, which is approximately 75 mph. And this means that they all drive at 130 km/h...
But when they don't have limit regulations, the slow idiots drive at 140 km/h. And this makes the Germans so, so, so unmeasurably angry. I mean, seriously, what kind of stupid, useless, piece-of-crap jerk drives at 140 km/h?!? The "normal" people drive between 150-160 km/h. And they complain when they have to pass a guy driving 140 km/h. But when I say "complain" I mean they bitch and moan as if the other driver were driving 40 km/h. Dude, it's scary. Really.
I come from a country where, when you're lucky, you may drive at 100 km/h, but that's totally unusual because the vast majority of our highways have an 80 km/h limit. So forgive me if I can't fathom driving legally at twice the max speed in my country...
You can do almost anything here in Germany. If the Germans don't like it, or don't approve of it, they will politely inform you. But please, please, pretty please, whatever you do, don't brake too close to a guy on a bike, and please, please, pretty please, don't drive under 150 km/h in an Autobahn. You don't want to see an angry German.
You really don't.