What I define as “common sense” may not necessarily be what others define as “common sense.” You can make a compelling argument that something that is “obvious” to YOU is NOT “obvious” to others.
It depends on one’s definition of what is “obvious,” and “widely agreed” to. Or if certain things are objective (which I personally agree they are) or not.
Also-----can one actually “develop” common sense? Or does it have to be inborn?
So what do you guys think?

Perhaps some quotes may help.
“For Cicero, common sense was primarily the common manner of feeling, the views of the crowd whose tastes the orator had to take into account if he were to influence them (
De Oratore, I, 3). However it was also an ensemble of spontaneous judgments with which all men are naturally endowed and which permits them to discern good from evil (
De Oratore, III, 50). This double meaning, commonly accepted opinion and opinion founded upon nature and reason, is almost always found in definitions of common sense.”
[Etienne Gilson, *Thomist Realism And The Critique of Knowledge. San Francisco: Ignatius Press, 1986, p. 32]
Although I do not side with many things in Rescher’s book, this I do:
“Neither individually nor collectively do we humans begin our cognitive quest empty-handed, equipped with only a
tabula rasa. Be it as single individuals or as entire generations, we always begin with a diversified cognitive heritage, falling heir to that great mass of information and information that constitutes the knowledge of our predecessors . . . . What William James called our ‘funded experience’ of the world’s ways—of its nature and our place in it—constitute the data at philosophy’s disposal to accomplish its question-resolving work. These specifically include:
• Common-sense beliefs, common knowledge, and what have been ‘the ordinary convictions of the plain man’ since time immemorial;
• The facts (or purported facts) afforded by the sciences of the day; the views of well-informed experts and authorities;
• The lessons we derive from our dealings with the world in everyday life;
• The received opinions that constitute the world view of the day; views that accord with the ‘spirit of the times’ and the ambient convictions of one’s cultural context;
• Tradition, inherited lore, and ancestral wisdom (including religious tradition);
• The ‘teachings of history’ as best we can discern them.”
[Nicholas Rescher, *Philosophical Reasoning. Malden, MA: Blackwell Publishers, 2001, pp. 15-16]