I think this is fundamentally incorrect, and the way we live today and the problems we experience bear this out. It's not about individual choices you make to engage with a cashier at Costco, it's about the opportunities to engage and where they occur. You're still talking about a forced connection you have to decide to make at the checkout line, and ignoring that you never see that person again in a different context, like in your own neighborhood or at your local restaurant.

Socialization isn't a choice one makes, it's supposed to be organic. The fact that you have to choose and make decisions around interacting with other people proves my point.