A culture without any form of currency is just bizarre. I can completely understand a de-emphasis on materialism, but there still has to be currency of SOME form, especially if other cultures (like the Ferengi) use them. And in early TNG, they said headaches were practically nonexistent. Again, this is just bizarrely unrealistic. They don't have any stress in the future? They face invasions, they have family squabbles, they compete for important positions... there is just no way in the world they've "cured" headaches.