In Daniel Keyes' novel, Flowers for Algernon, why is Charlie excited just before the surgery?

Charlie, in Daniel Keyes's novel, Flowers for
Algernon, is excited prior to the operation for two reasons. First, Charlie
wants to get smarter. He is mentally challenged, with an IQ of only 68. However, unlike
many people, he is motivated and easy to get along with. Charlie also takes night
classes at a local college to attempt to learn. The idea of getting smarter greatly
appeals to Charlie.

However, Charlie also is excited about
the surgery because of the guy he works for: Gimpy. Gimpy is Charlie's supervisor at his
job, and Charlie thinks Gimpy is his friend, even though the other man laughs at Charlie
and gets angry and aggravated with him. Charlie wonders what Gimpy will think and how he
will react when (and if) Charlie gets smarter. (There is some foreshadowing
here.)