Lately, I've been rethinking my understanding of friendship - that is, what it entails. Until now I have accepted that making new friends is a happy occasion because we gain someone new to share our life with, and losing them is sad because we will never have that person and their contributions back in our life. But now, I think it's more the other way around - making a new friend is a sad occasion because with it must come the acceptance that one day (maybe sooner, maybe later) you will lose them. Effectively you're dangling a treat in front of yourself, knowing full well that it will be snatched away again. On the other hand, losing a friend is a happy occasion - much as one can appreciate a friend when with them, it is only after losing them that you can really understand what they gave to your life. Losing a friend, while potentially sad, is a unique chance to reflect on the wonderful times you had with them.
A similar arrangement to T. H. White's Merlyn, but for different reasons.