I live on a hill, and the driveway ends below the house, so when we need to haul up materials (gravel, lumber, etc) for various projects, it's walking up a bunch of steps and slippery/muddy hills. I don't mind slopes on their own, and in fact quite like the exercise for every day use, but when you're hauling buckets of gravel or a cord of firewood, it sure would be nice if you could just load up a utility cart and walk it over to where it needs to be (or hell, drive your truck across the yard). It's not possible where we live because of the hill. So I can absolutely relate to why people don't like to live on a hill. And for hanging out outside with friends, you can't beat flat areas.

That said, the view is really incredible (we live in the woods) and we don't get water pooling in our place or flooding or anything like that thanks to some well-designed drainage, so, you know, pros and cons.