In Flowers for Algernon, how do Charlie's co-workers feel about Charlie having the operation?
Charlie's "friends" from his job as a janitor at the bakery were unaware that he had an operation to improve his intelligence. They have always enjoyed using him to be the butt of their jokes, and Charlie has always been oblivious of their selfish and cruel motives.
After the surgery, Charlie becomes aware of the true meaning of the teasing that has been done at his expense. As he advances at work, his co-workers are confused because they still do not know of the surgery. His friends who previously felt superior to Charlie, now resent his advancement and new-found intelligence. They resent it so much that they draft a petition to have him fired.
Ironically, what should have made his life better instead brings him sorrow. One of the old women at work wished that he would become "the good simple man" he was before.