Map of the California missions From San Diego to Sonoma, missions create a unique trail of history across California.
Those are still survival instincts
Being rejected, out meant death, very few could survive out side of the group.
Not finding a mate? Well that was at one time our strongest drive and it had to do with the survival of the species.
So at one time the fear was a valid fear, we still carry it though it is no longer useful.