Well i have noticed around were i live common sense ain't so common anymore!! computers don't teach a touch of it!

I have a very deep mistrust of 'common sense'. Too often people use it as a reason for doing something that releases them from having to consider the matter seriously. Although I think common sense is not always without merit, it always rings alarm bells with me when I hear the phrase.

Think you either have it or not. So born with it. My view and I am sticking to it.

Everyone has a different definition of common sense and nobody believes they lack it.

Common sense is learned. We all develop strategies for dealing with the outside world. Some people develop more effective strategies for pattern recognition and problem solving. Common sense is really little more than quickly diagnosing the situation and acting appropriately.

a bit of both i think

Common sense is kind of a misnomer. It assumes everyone has the exact same life experiences and learns the same lessons from those experiences. We all know those two things are an impossibly.

He is self absorbed-self centered.

Common sense is cultural, and learned from the culture you live in. Taking some ideas from below, it’s knowledge expected to be well understood, but not by humanity as a whole. Here it’s common sense to poop in a toilet, but it’s not uncommon for foreigners who are used to the common sense of using a squatting toilet, and will often stand on the seat and leave a surprise, we think they lack common sense, but they don’t.

In my experience, it is learned. Children really do learn what they live. Those children become adults, and the cycle continues. In my opinion, common sense does not discriminate and is often found to be the "common" denominator throughout communities everywhere.

I think common sense is something we learn or we don't, in the natural world, those animals that don't learn it become lunch.

I think it depends on DNA and environment. If you make a mistake and learn from that error it is a building block for common sense. However keep making the same mistake with no improvements you could have missed the elevator to the common sense floor.

Everyone is ignorant of many things. It is clear to me that I cannot learn or know everything nor is there a need to do so.
"Common sense is the collection of prejudices acquired by age eighteen." Albert Einstein (1879 - 1955),

Common sense is a basic ability to perceive, understand, and judge things that are shared by nearly all people and can reasonably be expected of nearly all people without the need for debate.

A key ingredient IMO for real common sense is curiosity. Without it, you have limited reasoning.

Based on my everyday interactions with other human being, most are neither born with it nor develop it.

I think we’re born with common sense. Some people just seem to have more of it than others. I also think we’re born atheist. It’s the indoctrination that makes people religious.