Time?
Peace of mind?
Close family ties?
Ties to a community?
I think the ties to a community are a big one. At least in the millennial generation, people are so caught up on social media and video games that they never get to know those in their community.
School friends and families? Yes. But other than that...not much.
It's unfortunate. I remember coming home when the street lights turned on around dinner time.
I hardly ever see kids out and about playing in my neighborhood anymore. I do, however, see them all on their phones nearly all the time.