Was about to say: girlfriend's best friend has the type of autism that makes him socialize with anyone and anyone who approaches him, because he believes in the goodness of all people, and thus can't seem to grasp the concept of ulterior motives. He's afraid of upsetting them if he doesn't engage, which caused issues for him and my girlfriend when they were walking alone in LA one night.

Thankfully nothing came of it, but he just could not understand why my girlfriend did not want to engage with literally every stranger who approached them on the street. The concept of "street smarts" does not exist in his mind. Reading between the lines isn't a thing for him.