I'm sorry I can't properly introduce myself, but I don't have a name anymore. (1.1.1)
It's hard to describe yourself if you don't have a name. If someone asked who you were, how would you describe yourself without using your name? I'm this guy, here. No, not him. Me—with the thumbs!
I am Perry Kelvin, a nine-year-old boy growing up in rural nowhere. (1.2.26)
Talk about an identity crisis. R starts to absorb Perry's memories and, in a way, starts to become him. By the end of the book, it's hard to tell the two apart. Which is creepy if you think about it for too long, so let's not.
Who are you? Let the memories dissolve. [...]
You're you again. You're no one. (1.2.43-1.2.44)
We can see why R gets so absorbed into Perry's memories (or the other way around, perhaps). As a zombie, he has no self-esteem or identity. He sees himself as no one.
"What are you?" [Julie] whispers. (1.3.17)
R responds, "I'm Sookie Stackhouse, and I'm a waitress." Okay, not really. He just groans and walks away, but if he had seen True Blood he totally would have made that joke with her. Jokes are a good way to deflect that you have NO CLUE who you really are.
Bodies are just meat. [...] The part of her that matters most... we get to keep that. (1.4.22)
This is a good way to look at identity. You are your personality, not the shell it resides in. After you die, it's your identity that will live on in the memories of others.
"I'm just... still alive. A wreck in progress." (1.7.60)
Julie identifying herself as a "wreck in progress" shows us that she knows she's made mistakes in the past and she's going to continue to make them. It may not be ideal, but at least she's realistic.
The person I am now, this fumbling, stumbling supplicant... was I built on the foundations of my old life, or did I rise from the grave a blank slate? How much of me is inherited, and how much is my own creation? (1.7.70)
Although this is R talking here, we could apply this philosophical conundrum to the lives of the Living. How much of our identity is predetermined by our parents, our genes, and the world we're born into? And how much do we make for ourselves?
Here we are. Trapped in the gap between the cradle and the grave, no longer able to fit in either. (2.8.36)
Is all of humanity having a mid-life crisis? Where have we been and where do we go from here?
Who is she, this girl? What is she? She is everything. Her body contains the history of life, remembered in chemicals. Her mind contains the history of the universe. (2.8.175)
Julie's not exactly special. The same could be said for almost any living person. We're all made of the same stuff, when it comes down to it. All that weight on our shoulders. No wonder so many of us have an identity crisis at some point.