system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happens when we remove a USB stick unsafely?
gpt
You risk interrupting an operation in the middle. Think of say, yanking somebody's notebook from them without asking. Maybe they were already done with it, so nothing happens. Or maybe they were in the middle of rewriting everything, in which case things get lost.

In general, these days systems count on people not complying with this rule all the time, and try to minimize the damage. But that doesn't mean damage can't be done. If you're doing something important, like say, giving a talk in front of people and were copying the presentation files to the drive, there's a chance you might find out it's not working when you put the stick in your laptop when on the stage. So best to make sure to do it the right way.