I love making maps. Drawing out the details of the land and making up the lore for the area really helps to flesh out the book as a whole. The difficult part was always trying to decide how the lands should be formed. Obviously, I had to shape a lot of it to match what I had written and things would get changed around as the story evolved. 
I look back at the first map I had ever drawn for the 7 Kingdoms, then known as 7 Nations, and I can't help but see how my cartography has evolved. I also get a smile at some of the names I had come up with and realise it was probably a good idea that I used more grounded names based on historical terms. It gives the world a genuine feel.
I have developed quite the interest in map making and cartography. It's become an addiction I can't shake. Spending hours stenciling the coastlines and watching the land take shape. It's just a shame that I suck so much at doing mountains. I've tried a hundred different methods, followed a hundred tutorials, but no matter what, my mountains look terrible.