USI

USI or Unidentified Sleeping Injury. Any new, idiopathic physical pain, ache or discomfort that you did not have when you went to sleep, but appears upon or shortly after waking, and for which there seems to be no apparent cause, such as recent trauma, injury, illness, effort or activity. USIs become significantly more prevalent after the age of 40. Often renders the sufferer extremely grumpy, and usually at levels disproportionate to the actual discomfort being experienced. This is because, at least in part, the advent of a USI reminds the sufferer that they are getting old, and their body does not work as well as it used to, when they were younger. Known to affect most human beings over time, no matter how healthy, fit or athletic they may be. Data on other fauna is not available, as they do not have voices to complain with if or when such a discomfort occurs. Most USIs resolve themselves within 24 hours without the need for any kind of medical or other intervention. Anything that persists beyond that time should probably be investigated, however, as the self-diagnosis of a USI may have been incorrect.