Many summers years ago, during an internship, I got tasked with setting up a development machine from old parts lying around the office. One of those parts was an, even at the time, ancient hard drive. When I first powered the computer up everything turned on just fine, but it couldn't recognize the disk. I'd run into bad hard drives before, no big deal.I went to my bosses boss, an older engineer who had seen a thing or two, and told him we'd need another drive. He took the thing out and gave it a good hard twist, and told me to try again. Lo and behold, it worked!

He explained that sometimes when older hard drives have been powered off for many years the head some times sticks to the platter and doing what he did can fix it. I could barely believe that the phenomenon was actually real. I've spoken to a few people over the years about heads sticking to platters and it turns out, while it isn't (or wasn't?) exactly common, it's not exactly rare either.