Whatever it is that makes closeness possible between two people also puts them in the way of hard feelings if that closeness ends.

In Part Five, Chapter 4, Jack reflects on his deteriorating relationship with Arthur. Once best friends, Arthur and Jack's friendship eventually survives only on the pain that they cause one another. Instead of accepting that they have outgrown their friendship, they perpetuate it with mockery and cruelty. This line embodies Jack's fear of intimacy and closeness, not only with Arthur but also with others, perhaps because Jack has not yet experienced love.