It's a long time since I've had to deal with slopes, although coming from Dunedin, I developed a healthy dislike of steep sections early on.
We lived on St Clair Hill and getting home from school meant walking up the (from memory) 284 steps of Jacob's Ladder, which led to our house.
More steep sections followed as I chased the warm weather north and finally, in Kerikeri, I got a flat section. A mate with a digger made a few very gentle contours to create a driveway and parking area, and to disguise the remains of the shelter belt I had cut down. I can walk straight out of the house on to the terrace, then into the lawn, and then into the orchard, without any discernable change of level. I am one happy person.
So I have sympathy for people who ask me how to design a garden for a hilly site. I stifle the urge to tell them to move because the advantage with a hill site is, of course, that you get a view. There are another advantages, too. Changes of level present an opportunity to alter the style or atmosphere of the garden without having to create the whole vista from scratch. And you can plant trees and shrubs of differing sizes in such a way that each is shown to its best advantage. With a flat section, you're always whacking the top of something.
Gardening on a hill is no problem provided you don't want flat bits. Just plant the whole thing in small trees and shrubs and ignore it. But if you want design elements and landscaping like steps, paths, walls and terraces, then you have a bit more of a mission.