There are three friendships which are advantageous, and three which are injurious. Friendship with the upright; friendship with the sincere; and friendship with the man of much observation: these are advantageous. Friendship with the man of specious airs; friendship with the insinuatingly soft; and friendship with the glib-tongued: these are injurious.
ConfuciusTo take what you know for what you know, and what you do not know for what you do not know, that is knowledge indeed.
Confucius