Common sense the least common of senses

Whenever I hear this phrase I understood  "common sense" was something special, for that, rare, a rather uncommon quality. Over time, and taking time, I have ended thinking that it is not. Of course we all have "common sense" so, you could say that it is actually, as common as other "senses". Simply we each have our own, which makes  it  rare. Am I messing it?.

First things first :

Common Sense. Definition:
1.Knowledge and beliefs shared by a community and regarded as prudent, logical or valid. This is the natural ability to judge events  in a reasonable manner.
2. Plain ordinary good judgment; sound practical sense.                                                
3. 14c., originally the power of uniting mentally the impressions conveyed by the five physical senses, thus "ordinary understanding, without which one is foolish or insane" (L. sensuscommunis, Gk. koine aisthesis); meaning "good sense" is from1726. Also, as an adj., commonsense.

Is that clear?, Maybe not...

• Knowledge I agree, but some have more and some might have less.
• As for beliefs, everyone has their own  beliefs and when you belong to a community you will accept the "general beliefs" as your own but that is happening less and less within the western society.
• The fact of being reasonable and the adopt the general thinking is what spoils the whole thing.

There are basic concepts in a society which are established and generally accepted as "reasonable" , okay. But in an increasingly individualistic society,  more multicultural and with less community spirit, the concept of "fair" and "sensible" becomes more diffuse. Ex: Based on my knowledge,  in my beliefs and  my cultural background, I consider reasonable "marriage" between individuals of the same sex. At the same time within my own community, others consider that possiblility an aberration and in other cultures (which can be represented within my own  community I) the simple fact of being gay is considered a crime.

Common sense is directly related to the reasonableness, rationality and social life. Without standards of behavior established and accepted by the majority is not possible a peaceful  community.

Of course there are exceptions to everything. Some might look funny but that says much  about those  exception and how society accepts them: "Anyone can have a bad reaction /a weak moment", And then of course it comes, "Nothing ever happens until it happens," and "that you can does not mean you should" or  "you should have thought  before doing it."

Let´s think!