Even if you consider yourself someone with a good memory, you likely don't compare at all to people with hyperthymesia. People with the condition can remember nearly every tiny detail about every day of their lives. There have only been a handful of cases identified worldwide. The word itself stems from the ancient Greek word "hyper" (meaning "excessive") and "thymesis" (meaning "remembering"). Neurobiologists have identified two traits of those with the condition: spending a lot of time thinking about one's past, and "displaying an extraordinary ability to recall specific events from one's past." Different from those with exceptional memory, people with hyperthymesia involuntarily recall events quite vividly.