Although seemingly ill equipped as the narrator of a book, Christopher's character succeeds in eliciting a wide range of emotions in the reader.

Your teacher hit the literal nail on the head with this question. Why exactly does Christopher's narration touch us? Well, that would be because as a narrator, Christopher only says what he means literally. He never intends to be funny, he never intends to make us cry or even smile. He just calls it like he sees it because to him it's just a story, but for us, it's a glimpse into the quirky mind of someone we might not have ever taken the opportunity to understand.