It took me a long time to figure out what I wanted to write this week, because everything I came up with turned out being part of my review for tomorrow. So, even though I didn't cry at this book and I don't think it even broke the top twenty or thirty saddest books I've ever read, it seems everyone else who has read it has a soggy copy of the book because sad. So let's talk about crying.
Why cry? Babies do it as a communication tool: "I am unhappy about something and I lack the verbal skills to tell you what it is, so I'm going to cry until you guess correctly." That works for adults, too: "I'm unhappy and either need you to do something about it or show me support." It's cathartic: "I feel unhappy, so I'm going to cry until I feel a little better about whatever is making me unhappy."
Who cries more? The APA found that women cry an average of 5.3 times per month, while men tend to cry 1.3 times per month. (Don't ask me what 0.3 cries looks like.) It has been proposed that testosterone inhibits crying, and prolactin encourages it, which would help explain that. Also, people who live in countries/areas with more freedom of expression cry more, and people who feel more secure in their attachments and relationships cry more.