Conversation so far:
What is a typical character for him?
Simon's characters are typically portrayed as "imperfect, unheroic figures who are at heart decent human beings".
Does he act as characters?
He reproduces speech so "adroitly" that his characters are usually plausible and easy for audiences to identify with and laugh at.

Question: How does he come up with ideas for his characters?
Self-contained rewrite: How does Neil Simon come up with ideas for his characters?