“It's pretty amazing how uncommon common sense is.”
“Remember, the most common thing about common sense is how uncommon it is.”
“There is nothing more uncommon than common sense.”
“Common sense has become an uncommon virtue.”
“Common sense in an uncommon degree is what the world calls wisdom.”
“Common sense (which, in truth, is very uncommon) is the best sense I know of: abide by it; it will counsel you best.”