I bought this book not for a child but for a close friend who is going through a very difficult time in his life. I picked it based on the title alone, because it seemed like it'd have the sort of message I wanted to share with my friend. When I read it, I was delighted by the very simple story of two characters trying to define the size of their love, in a way very much like a game I used to play with my mother. Some people feel that the story is very competitive and I can understand that opinion, but I never felt that way when I played that game with my mother, nor does the book feel competitive to me. To me, the message is simply about love, and the undefinable, unquantifiable nature of it, and the way that no matter what kind of analogy you create for how much you love someone, it's still not big enough.
Besides the message of the story, and soothing illustrations, what really made this book a favorite was the lack of definition for the relationship between the big and little hares. A lot of stories mention in one way or another how the characters are related, and usually they're parent and child. This book makes no mention of how the two characters are related, or even if they are related in any legally-recognized way; you can take it to be whatever you want, whatever fits. Because of that, it's a particularly good fit for our odd mentorship-friendship, or any other nontraditional relationship.