A geographical feature that has had both positive and negative effects on a nation or region would be ocean. An ocean like the Pacific Ocean can be able to provide a region with seafood to help a civilization developed with a surplus of food. An ocean could also allow a region to create a trade route between other regions, this can be proven true because the Atlantic Ocean was used throughout history as a major trade route from Europe to North America. A negative effect of an ocean would be that a nation can be more susceptible to tsunamis. For example eastern Asia could be more easily open to this because there are a lot of archipelagoes that are surrounded by a lot of water. This would destroy all of the land close to the ocean, which would leave you without shelter and crops. This would eventually lead to starvation which may cause people to migrate over to a safer place.
Geographical features have been part of history, and have made the world what it is today. These features could even provide protection for a civilization that is trying to develop. This is way before a civilization actually settles they make sure of how they will use their new surroundings.