The first, an Arabian proverb, is of the inspirational kind: 'A friend is one to whom one may pour out all the contents of one's heart, chaff and grain together knowing that the gentlest of hands will take and sift it, keep what is worth keeping and with a breath of kindness blow the rest away.'

The second, an observation of Stephen Fry, is of the arresting kind: If you have genital warts, your friend is the last person you show them to. You go to see a complete stranger, a doctor. If you have the psychological equivalent, like depression, you do not want your friends to see it either. Another stranger is better, a therapist. So the idea that friends are always the people you want to see in times of trouble is, I think, not right.

The third is a masterpiece in the witty and profound wisdom of Slavoj Žižek: 'When, after being engaged in a fierce competition for a job promotion with my closest friend, I happen to win, the proper thing to do is to offer to withdraw, so that he will get the promotion, and the proper thing for him to do is to reject my offer - this way, perhaps, our friendship can be saved.'