AT THE END OF THE STORY, WHAT WAS THE SAD REALITY THAT MADE NICK VERY FRUSTRATING TOWARDS THE PEOPLE AROUND HIM?

Nick hates the people around him. They are vacuous self-indulgent ghosts of real people. Although thousands of people attended Gatsby’s parties and enjoyed his hospitality, none, including Daisy, will attend Gatsby's funeral. Nick sums these ideas best near the end of the novel when he tells Gatsby, "You're worth the whole damn bunch put together."