So, a while back, I had this idea. I had a pretty beat up old futon, and thought maybe I could get a bit more life out of it if I added a bit more springiness to it. Box springs! Those would help, right?
The futon does not distribute weight in the same way that a mattress would. This means that the box springs get squished and deformed. But wait! They do not get squished and deformed in some nicely consistent way, so after a year or two, you have a sort of bathtub-shaped device full of poky bits of metal, which cause the futon to be sort of bathtub-shaped but with little poky areas.
This results in sleeping poorly.
I think it says a lot about my usual level of awareness that it took me six months to a year to figure out that I was not sleeping well.