Probably best not to follow this advice for people, but certainly a good idea for your misbehaving computer, modem, router, or printer.
Unplugging a device, plugging it back in and turning it back on causes the machine to re-initialize, often repairing its own abberant behavior. It’s not always the fix, but trying it can’t hurt.
To re-initialize laptops, smartphones and tablets that run on battery, power down the machine and restart it.
If your machine is frozen and cannot be powered down properly, hold down the power button (sometimes in tandem with the “home” button) and wait until the machine goes dark.
Sometimes rebooting is all the “life support” you need.