For me it is the fact that our blood contains iron. I earlier used to believe the word stood for some ‘organic element’ since I couldn’t accept we had metal flowing through our supposed carbon-based bodies, till I realized that is where the taste and smell of blood comes from.
I really get the feeling that this question isn’t being asked seriously but here goes.
Floppy disks are an older removable storage format for a computer. The media inside the disks was flexible like a piece of paper, hence the term “floppy”. There were three different common sizes, there was an 8", a 5.25", and a 3.5". The 8" and 5.25" had the flexible media in a sort of heavy fabric and plastic sheath that was itself flexible, amd the 3.5" disks had a hard plastic cover on the outside, with a sliding metal door, and some people erroneously called these “hard disks”.