When my great-grandmother died in the mid-90s, we found a number of questionable collections in her house, including a paper bag filled to the brim with meticulously cleaned-out egg shells and a very toxic jar of mercury she had drained from old thermometers. In short: She was totally a hoarder. Had she lived to see the age of reality television, we could have put her on A&E's Hoarders, which tracks the lives of people who obsessively collect and can't bring themselves to throw things away, even to the point of creating dangerous, trash-filled living situations.

Though its not yet considered an official disorder, somewhere around 5 percent of Americans, or 15 million people, struggle with compulsive hoarding, as Bonnie Tsui noted in her in-depth look at the science of hoarding in Pacific Standard.