Given my understanding of human nature, it is easy for even good workers to descend to become parasites if they are rewarded for being lazy. Some professors slacken after getting tenure.
In the Star Trek world, there is no longer any motivation to work hard and tolerate stress because there is no need to work.
How does the Federation compete with the hard-driving money-driven Ferengis? If you are an investor, it is so obvious who you would long and short.