Equality mentions he has a curse. What do you think his curse is and why does he think of it as a curse?

Equality's curse is his desire for knowledge. He considers it a curse because he isn't "allowed" to know..... his desire is considered a crime.

And it was our curse which drove us to our crime. We had been a good Street Sweeper and like all our brother Street Sweepers, save for our cursed wish to know. We looked too long at the stars at night, and at the trees and the earth. And when we cleaned the ard of the Home of the Scholars, we gathered the glass vials, the pieces of metal, the dried bones which the had discarded. We wished to keep these things and to stud them, but we had no place to hide them. So we carried them to the Cit Cesspool. And then we made the discover.