I'm usually too excited to sleep the first night, but after that I have no problems.

I have found that a sufficiently warm sleeping bag and a really comfortable pad are the keys to getting a good night's sleep. What is comfortable varies according to your age, how you sleep, the condition of your joints, etc. I need a 2.5" air pad, blown up about halfway (just enough to keep my hip off the ground when I'm on my side) to do the job. Your Mileage May Vary.

I strongly recommend spending several nights at home on the floor with a new sleeping pad. 15 minutes in the store is not enough. Test the pad thoroughly at home while you can take it back in new condition.

No doubt the hammockers (I spent part of the weekend with four of them) will chime in about the comfort of their setup. As I said, YMMV!