I refuse to give up my obsession. (23)
Does it help that the speaker acknowledges his own kinds of madness? It seems like we trust him more when he does admit that he's got his own mental issues. It's like he's not excepting himself from the madness that's around him, and yet he still manages to be sane enough to critique what he sees.
My psychoanalyst thinks I'm perfectly right. (34)
Well, then. By all means, carry on. Why does the speaker feel the need to add in this vote of confidence from his psychoanalyst? Is he worried that we won't believe him? Ironically, does the fact that he has a psychoanalyst cast doubt on his mental state as you see it?
I'm nearsighted and psychopathic anyway. (79)
This is an interesting admission, coming right at the end of the poem. On the one hand, it could be seen as just another joke the speaker is making. After all, nearsightedness and psychopathy are a pretty odd combination. On the other, he may be divulging to us that he is genuinely insane. The main point, we think, is that the speaker's mind is part of what sets him off from mainstream society. Once again, he reminds us that he doesn't fit in to the world that he's critiquing.