system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When you "sell" stocks, who is buying them? What if nobody wants to buy them? What if nobody wants to sell them? How do they work?
gpt
When you sell a stock, as in you've hit the "sell" button on your trading platform or called in an order, you're selling it to someone who has hit the "buy" button on his trading platform for the same price. 

If you sell and no one wants to buy, then your order will just not be filled at that price. Then, depending on your choice of broker or personal settings, your order will be canceled, wait to be filled at the price, or fill at the next available price(s).

So pretty much, when you sell a stock, you're selling to some guy who happens to be buying at that moment. If no one's there to buy from you, you'll be left hanging. And vice versa.