It is sometimes said, common sense is very rare.

"Rarus enim ferme sensus communis in illa Fortuna."

["Generally common sense is rare in that (higher) rank."]

Common sense ain't common.

... dans tout combat entre le fanatisme et le sens commun, ce dernier a rarement le dessus.

common sense is no t always common

Common sense is as rare as genius.

common sense isn’t always common action.

Sense is never common.

It may be expecting too much to expect most intellectuals to have common sense, when their whole life is based on their being uncommon -- that is, saying things that are different from what everyone else is saying. There is only so much genuine originality in anyone. After that, being uncommon means indulging in pointless eccentricities or clever attempts to mock or shock.

Common sense in matters medical is rare, and is usually in inverse ratio to the degree of education.

Because I have common sense, OK, and unfortunately a lot of people don't.

We rarely think people have good sense unless they agree with us.

But feeling is so different from knowing. My common sense tells me all you can say, but there are times when common sense has no power over me. Common nonsense takes possession of my soul.

Nonsense is so good only because common sense is so limited.