Fyodor Dostoevsky.

Every man has some reminiscences which he would not tell to everyone, but only to his friends.

He has others which he would not reveal even to his friends, but only to himself, and that in secret.

But finally there are still others which a man is even afraid to tell himself, and every decent man has a considerable number of such things stored away.

That is, one can even say that the more decent he is, the greater the number of such things in his mind.