> If you walk directly up to someone and it isn't a natural connection, everyone will always assume your trying to sell them something or bother them in some way.
The point of my comment is why this is happening. The reason "everyone" (in the US) assume that is because that is typically the reason. Because the typical people who approach us in the street are panhandlers and marketers.
It's like the early year of SPAM. When email just started, messages would usually receive attention, since they were usually from genuine people looking to connect. Then SPAM started, and many people started ignoring email completely, to the point it became effectively dysfunctional as a communication medium. It required an extensive, aggressive campaign to fight off SPAM, until email because a functional medium again.
In the same way, if somehow panhandlers and marketers stopped approaching us, we would be more open to socialize in public spaces, because we wouldn't assume (quite appropriately, as of now) that any stranger who tries to talk to us is just looking to get something from us.