I can sleep on any floor. I'm happy with hard surfaces and have no trouble at all with floors. So if there is a big family get together and not enough beds just hand me a doona and a pillow and I'll be right.
I can't sleep on the floor. I find it almost impossible to fall asleep anywhere other than a bed! I fell asleep on a train once, after a weekend away when I had got no sleep at all... luckily the train terminated at my stop, so I still managed to get home! Otherwise, even lying on a settee I might be able to doze lightly but not sleep properly.
Would have to put down thick covering firstly, as there's something in/under/on carpet that gives me an instant, throbbing headache. It's a smell.
Have had this problem since a kid, & could never play on carpet!
I've had to sleep downstairs on the floor (but with sleeping bag padding) on hot nights. Though I find it gets like the princess and pea situation, where I can feel the floorboards (only thin carpet) on my spine and wake up every couple of hours.