Being German myself, I wouldn't necessarily say that we're inherently hard workers...
Why, plenty of people I know are lazy asses like any other on this world
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The crucial difference is that we're easily roused / quick to get to work if the situation demands it. Competetive, maybe. Even now, I'm currently in Croatia visiting relatives on a farm. It's anything but a holiday, I can tell you. All I get is farmwork :D . Fact is, if I was left to my own devices, I probably would just laze around all day. But the situation requires me to get up and get work done, so I do just that - rather efficiently, too.
Maybe Germans on average just like a challenge, though I'm not about to put that down as fact
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