In "Flying Lessons," what does Santosh say is his "deal with the devil"?

Santosh explains that his deal with the devil is that he can have all the success in the world, but no one will actually like him. From his perspective, he has trouble making friends. He feels the other boys are cooler and more attractive, more athletic, with perfect vision. His revenge is to excel in school, to make their parents sit through awards ceremonies where he wins everything. How, ultimately, this is another example of what his grandmother is trying to teach him: that his focus on studies and awards deprives him of the chance to be interesting and to make friends.