When discussing the idiocy of people, some people will laugh and say, "HA! Common sense isn't so common, is it?" What they're really saying is "good sense" isn't common, and that is true.
What isn't true, however, is that "common sense" equals "good sense". What is more common, it seems, is "
bad sense". The fact that "bad sense" is common makes it "common sense". Does that make sense? HA!
Common means "of or relating to a community at large", according to
Merriam Webster. It also means "occurring or appearing frequently" and also "falling below ordinary standards".
So, the community at large seems to have "bad sense", and that makes their sense the "common sense" of the masses, or their general and similar sense. When people say that Sarah Palin is a common-sense candidate, they are absolutely right. She represents the overall bad sense of a large majority of the population. This, however, is NOT something to brag about. Again, "common sense" does not equate "good sense" even though people understand the phrase to mean "good sense".
Am I being picky? Yes. I am. People should understand the words and phrases they regurgitate after ingesting their culture's mantras. If someone accuses you of not having "common sense", you should take it as a compliment. What you want is "good sense", and that is very uncommon.