Without the humor, we should be worried about Greg. This line tells us how bad he feels at school because of the simple fact of existing. Imagine how bad he must feel to look a solution for his existence. He probably feels as if he does not belong in there, like a freak kid that everyone makes fun of him. He can create depressive behaviours such as isolation, sadness, etc. that can lead him to, dramatically speaking, commit suicide. This is not a joke, he is probably having a mental illness because he does not feel comfortable with his life in high school.