As a not-too-distant relation of Dylan Thomas, I make no apology for quoting here an extract from one of his letters, which I rather like:
"Shall I give you a lecture on Norman? .... all Norman needs from a friend is friendship, and friendship, to him, is only acquaintanceship that has gone on for sufficiently long. He has never tried a friend's friendship to the full, is ignorant to the extent to which real friendship can be tried; and, therefore, when his own friendship is tried, it fails. It fails through his lack of experience: he can open his heart to let lots of people in, but he can't open it out altogether for one person: he covers his heart with half-friends to conceal it's nakedness from the advances of a whole friend: he doesn't understand that a real friend is always naked, that a real friend doesn't have to undress but that he just has no clothes to wear in front of him,... He can't understand that people are bound together because of what they give out to each other, not because of what they offer to each other (and a companion is always offering.. while a friend is giving out all the real, warm things)."