I hated that question when I worked at a bookstore-- because I think each person is looking for something different.
That said, tiny beautiful things is capable of being at least something to lots of different people. It's an honest gut-punch, a loving validation, a pull-your-pants-up-and-get-on-with-your-life kick in the teeth from someone whose prose is so raw, so honest, so loving that even when the letters weren't about things that hit me too close to home, sometimes I still had to put the book down for a bit and just *gasp* at the truth of whatever it what Cheryl Strayed had just written.
I say this as someone who has only gotten halfway through Wild, and put down her novel about two chapters in.
This book is different.
This is tough love, self love, real love, true love. It's not all the love you'll ever need between two orange paperback covers, and it's not the only book you'll ever need to cure whatever ails you-- but it's one that will help. And which you'll turn around and start buying in stacks to hand out to your friends, even though you'll find yourself saying, as I do, "I'm not much of a self-help book person, but..."