Humans as Machines

I find it difficult to categorize humans as machines, even though is pretty hard to argue that we aren't made up of countless tiny machines inside our bodies. I can't claim ignorance after learning a little bit about molecular machines but I just can't take that leap of faith (or lack thereof) and say that humans are just machines. There's something that sets us apart from every other animal, cell, plant, etc. but it's hard to determine what that is exactly. It could be our ability to make rational decisions, to learn, to think for ourselves, our free will- I don't really know, but, as far as I'm concerned, humans aren't machines.