Avoidance psychology

The mind being wired to do something it PERCEIVES as a bit risky. Can be from first-hand experience, or from what they hear from others, or can be from their own logic (rarely), or just fear of the unknown.
For example: “STRANGER DANGER”
Passed by parents, telling them to avoid strangers
Later, blamed for "lack of experience with communication " or "lack of friends" (school, which is pretty much the only place left, tells people to be quiet during class) 1. but everyone is a stranger at first! 2. so if you actually follow their advice to the full, you would end up as a total lone wolf! 3.no marriage, as even marriage partners are strangers = humans go extinct!

Strangers usually have no reason to harm, you know. Other than statistical outliers like murders, because they have zero expectation that anything would happen, so even talking would be more than they expected. However, they are less likely to do favors or tasks that take long amounts of time than friends.