Mostly the space enthusiast working for NASA suffers simple discouragement. And over years, this can eat you alive. Good ideas ignored, bad ideas pursued, and goals seemingly irrelevant. I have only worked on NASA contracts, and never been a direct employee, and speak only from second-hand knowledge here. NASA employees here are welcome to jump in here.

The bureaucrats aren't evil, they're just bureaucrats. The object of the game is to keep the system going, keep the budget fat, and keep the number of employees large. Actually accomplishing something falls somewhat further down the list.

People who have worked for large corporations will be fully aware that these type of people are not confined to the government. There is a reason that real innovation, while not unknown in large, established corporations, is found much more often in new, smaller companies.