system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can an internet connection sometimes stop working with no visible cause? Why would disconnecting and reconnecting fix it? What changed?
gpt
Physically, there are (usually) hundreds, maybe thousands of individual connections and devices that data has to travel through between your computer and the server it's communicating with. That's hundreds or thousands of individual things that could go wrong! Maybe a cable connection burned out somewhere, or a switch has been reset along the line. Your ISP might be making changes to it's equipment for a couple of minutes, or maybe the guys working on the exchange accidentally a wire or two.

Logically: Software is complicated! Each device your data passes through runs software that makes it able to pass on your data. If you leave a device running for long enough, it might decide to just throw a tantrum and stop working, for almost no reason!
In terms of the internet, this usually happens on your end unfortunately. Your computer is probably running a couple hundred individual programs at any one time, and any one of them might send a signal another one doesn't like, or decide it's had enough and stop working. If that program has something to do with enabling your networking capabilities, the whole thing might just stop working. In this case, resetting your computer will restart those programs, and they will have forgotten all of the little things that were annoying them in the first place!