system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is that wierd jarring feeling when you take a step on the stairs and don't realize it's the last one? Isn't it just like every other step?
gpt
You mean when you get to the top of the stairs and try to take another step because you don't realise you're at the top? Your body was prepared to put your weight on top of the next step, but there isn't one, so you lose your balance and fall forwards until your foot touches the *actual* floor. It's basically the same as if you were walking blindfolded on the flat ground, and you stepped in a pothole which you didn't know was there.

Walking is actually really complicated even though our brains make it seem easy. (That's why most robots use wheels instead. Wheels are much easier.)