Here's one you should only try if the circumstance dictates, but as with any new-fangled piece of tech, there's going to be unforeseen errors that happen along the way - especially as new firmware updates roll out that shake everything up. So say you've got a DS4 that won't pair up, or any part of its functionality is unresponsive, simply grab a pin or other thin implement and gently push it into the hole shown above to reset it's internal memory and - hopefully - restore it to working order again.