After living in Stuttgart for the last 5 years, I can tell that these stereotypes describe some Germans perfectly well but the important thing here is those account for less than 1% of the population.
The remaining 99%? Those are these very friendly people who have this amazing ability to be relaxed and efficient at the same time.
I live there, and in my experience, Stuttgart is not a very good city to live in, and I know quite some people who share that sentiment. Swabians are famously unapproachable, though I do respect them a lot.
Thats one reason I'm moving to Munich - anyone knows a good company to work for there? :)
The remaining 99%? Those are these very friendly people who have this amazing ability to be relaxed and efficient at the same time.