I totally get this - In my youth, I  lived ont he steets of London for 18 Months - No Beds there and Cardboard was actually pretty good ( when it was dry") 
But I have lifted myself up in more ways than one. I now sleep on a Bed but with a very thin hard mattress, The problem with being on the floor is that  you get all the Bugs , Dust and Dirt and, in winter, the Cold....