The story

It happened when I unplugged my laptop's power source. The battery indicator started blinking, but I wasn't paying attention to it; my main focus was on the external monitor. I have a script running as a systemd unit that turns off the monitor when the battery percentage drops below 5%, and it really works to notify me of what's happening. I immediately realized that my battery was running low!

I never thought it would be useful as my laptop is an advanced one; it supports a feature to stop charging on a specified threshold, so I thought writing such script would be wasteful, but turns out my perspective is completely wrong, and in some cases it could be really helpful!