That's what I thought when I was 20, but social interactions don't happen by osmosis. Walking up to a stranger in a coffee shop and talking to them is actually quite strange, especially if everyone there is working.

You're better off with shared interest groups: exercise clubs, hobbies, that sort of thing. It's like the social parts of work, but you don't get paid for it and you don't have to leave when you move to a new job. You can even go out as a group in the evenings after the activity ends if you want to, just like work!