"Fuck You" money is an illusion that keeps you working. The mind loves to believe that having enough of some external thing will give us control, safety, or whatever we most fear the lack of. It isn't true. A man with with excess money is absorbed in concerns of what to do with it and is hardly free. He might be able to say "fuck you" to people, but he can't say "fuck you" to money.
Freedom is measured by the scarcity of our concerns. And happiness, perhaps, by closeness with people to whom we need never say "fuck you" because we love them and accept them fully.