Sleeping in a hammock is definitely different for everyone. I have to say very few have gone back to the ground though. Dialing in the right heights on the tree is a learning curve. There are a lot of factors that go into it. I do recommend getting the book The Ultimate Hang. It's full of great illustrations and advice, like this forum.
I agree with FLRider on his answers. I kept sliding down towards the foot and over several nights raised the foot suspension and found the right height.