The sad truth is that strangers almost always want something from you. The primary three motives are money for the bus, your eternal soul, or sex stuff, so any uninvited contact is met with justifiable skepticism.
Another barrier to unprovoked introduction are handheld 4G loneliness shields. It's easy to look like a loser when you're alone in public, so thankfully smart phones function as cocoons to isolate you from being bothered by weirdos. It's where all your Real Friends are hanging out, who just so happen to be Instagram models and New York Times writers.
In the rare case that you have a third party to introduce you to this mustache-wearing cyclist, the quality of the intro is pivotal. Shaking hands and exchanging names is the first step, but you won't remember this person's name without an actual conversation. If you do remember and use it at a later time, you're once again in creep territory, so be ready to make like Skyler White and tread lightly/not process information from previous episodes.