Common sense is the collection of prejudices acquired by age eighteen. He that leaveth nothing to chance will do few things ill, but he will do very few things. People only see what they are prepared to see. The eye sees only what the mind is prepared to comprehend. A group of the unwilling, picked from the unfit, to do the unnecessary.
Some people have a large circle of friends while others have only friends that they like.
Foolproof systems don't take into account the ingenuity of fools. The quality of an organization can never exceed the quality of the minds that make it up. Man is the only animal that blushes. Or needs to. The radical of one century is the conservative of the next.