- The US is a low trust society
- European culture typically places less emphasis on workplace friendships compared to the US.
- As an another commenter said, the size of US cities. But also the difficulty & cost of getting around
- There is something about the American demeanour that is surface-friendly, but also seems to discourage deeper/emotional connection. Whereas many European cultures can seem less smiley-friendly, but also more honest and genuine
- I feel like the very strong Protestant work ethic in the US may play a factor. When productivity is so important I feel that must detract from other aspects of life (stress, free time, relocations)