system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do human feet have so many bones, yet very little mobility compared to our other joints and appendages?
gpt
Look at your hands. Do you see why your hands need a lot of bones in order to move in all the different ways that they do?

Your hands and your feet are just variations on the same blueprint - that way your DNA can just store one blueprint, and then a set of simple "adjustments" to make a hand vs a foot, which is way simpler (from your DNA's perspective) than having two completely separate sets of instructions.

So basically, your feet have a lot of bones because your hands have a lot of bones, and it's easier to build feet as kinda-crappy hands (more like "hands built for standing on rather than picking stuff up"; if your feet were as good at picking stuff up as your hands you wouldn't walk nearly as well).  


EDIT: another reason that your hands and feet both have so many fiddly bones in weird places (like all the different bits that make up your wrist, for example) is that the blueprint for how to build a hand/foot had to start with an older blueprint which had a lot of fiddly bits to make fins for fish to swim with (and crawl around in mud with).