system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do some clocks run slow or fast, regardless of being digital or analog?
gpt
Clocks are mechanisms/circuits that are designed to run at a fixed rate, and they are very good at that. There is only one, perfectly precise rate that is neither fast nor slow. It is impossible to hit this exactly, so every clock will be either fast or slow at a given moment. Most clocks are pretty damn close though, so you perhaps wouldn't notice.

Think of it like this: there are an infinite number of fast or slow rates, but only one precisely correct rate.