Who wrote the poem in perks of being a wallflower

Read the excerpt below from The Perks of Being a Wallflower by Stephen Chbosky and complete the instruction that follows.

Wow. Wow. I can paint the picture for you if you like. We are all sitting in Sam and Patrick's house, which I had never seen before. It was a rich house. Very clean. And we were all giving our final presents. The outside lights were on, and it was snowing, and it looked like magic. Like we were somewhere else. Like we were someplace better.
It was the first time I had ever met Sam and Patrick's parents. They were so nice. Sam's mom is very pretty and tells great jokes. Sam said she used to be an actress when she was younger. Patrick's dad is very tall and has a great handshake. He is also a very good cook. A lot of parents make you feel very awkward when you meet them. But not Sam and Patrick's. They were friendly all through dinner, and when dinner was over, they left so we could have our party. They didn't even check on us or anything. Not once. They just let us pretend it was our house. So, we decided to have the party in the "games" room, which had no games but a great rug.
When I revealed that I was Patrick's Secret Santa, everyone laughed because everyone knew, and Patrick did his best impersonation of being surprised, which was nice of him. Then, everyone asked what my last gift was, and I told them it was a poem I read a long time ago. It was a poem that Michael made a copy of for me. And I have read it a thousand times since because I don't know who wrote it. I don't know if it was ever in a book or a class. And I don't know how old the person was. But I know that I want to know him or her. I want to know that this person is okay.
Source: Chbosky, Stephen. The Perks of Being a Wallflower. New York: Pocket Books, 1999. Google Books. Web. 16 May 2011.
Explain how the voice of the passage affects the characterization of the narrator and the other characters.