I finally told one couple my dad kicked their dad's asses on Utah Beach.
~but most Germans I’ve met were extremely arrogant~
True. I thought about this too. Germans are perfectionists of the highest grade and any sign of ‘imperfection’ is really annoying for them. Their worst nightmare is not to make things done, or make it bad (bad = below 100% perfect by their book). They are in constant stress for that reason.
Needless to say that anyone who has different perception of life (or people of any other culture, probably with the exception of Japanese who actually resemble the Germans on that matter) considered annoying imperfections which makes Germans mad.
That is a background behind a German arrogance. On the other hand, Germans are mostly emotionally dude. It contributes to their inability to communicate with people, including between themselves.
It is a primary reason why their mechanical perfection hasn’t conquered the world. No matter how able you are to make things done, you won’t force your way against the rest of ‘imperfections’ who you despise and fail to communicate with.