A small startup has just released a study about stress levels in various cities - and Stuttgart came out as the world's least stressful place:
https://www.zipjet.co.uk/2017-stressful-cities-ranking
It is of course possible to prove whatever you want with statistics like what the study contains - but it certainly serves as a discussion starter:
What do you think about the level of stress in Stuttgart or other German cities, and how does it compare to your home country?