To most people, the idea of being a genius sounds great. And Charlie's no exception. As someone with serious learning disabilities, he's especially keen on the idea, as he believes that being a genius will earn him the kind of admiration and respect that he cannot get in his current life.
Charlie says that he knows and loves many people, but they don't seem to respect him. As he tells us, they laugh at him and despise him for his "ignorance and dullness." One can understand, then, why Charlie is initially such a keen participant in an experiment designed to enhance his intelligence. He evidently figures that being a genius will give him the respect that he deserves.
Unfortunately, it doesn't work out like that. As Charlie admits, his status as a genius has driven a further wedge between himself and the people he knows. His coworkers at the bakery, who used to make fun of him for being slow, hate him even more now that he's super smart. In fact, they hate him so much that they band together to have Charlie fired.
There's clearly an element of inverted snobbery here in that Charlie's coworkers resent the fact that he's so much smarter than them. Far from being geniuses themselves, they can't handle being around someone who really is a genius.