As with your example of the knife+outlet, some common sense is acquired via experience. Same with playing on the freeway...it will teach you the harsh realities of physics very quickly!
What we all need and I think want is the ability to reconcile our desires with reality and acquire knowledge without the pain and suffering of shoving a knife in an outlet.
It is popular to point out that in "the past" this was commonly done through intergenerational interaction, and that this interaction is becomming less common due to the breakup of the nuclear family (where the parents and offspring lived with each other or with multiple generations under one roof or within close proximity. It's often referred to as "The Walton Family" experience...referring to the popular TV show of the 70's which depicted grandparents, parents, and children all living together in one house. There is a lot of truth to this.
But just living together won't magically pass wisdom from one generation to the next...it requires attitude. Specifically, an attitude of respect. The "they've been there done that" kind of respect that presents a young person (and sometimes an old person) to be a willing recipient of "truth" from someone else.
It doesn't have to be family. Many people find that kind of common sense through various schools, public and private, trade and fine arts. Some find it in the work place with mentor relationships.
The one necessary ingredient that is often missing though, in my opinion, is the attitude of "they have something I can learn"...without which there's little chance of acquiring anything of value, let alone common sense.
Thank you for posting something of great value! Keep thinking like this!!!