6. Barbarians are much more aggressive than I remember from 5. If their scout sees your capital, they will come with a vengeance. Turn them off, and other civs will expand unchecked, making forward settling (founding a city near your lands, often crossing lots of fecund, unclaimed space to do so) by the AI a huge problem. 7.
https://www.amazon.com/Sid-Meiers-Civilization-VI-PC/dp/B01FEHJYUU