All rights reserved. Thomas, via AOL Glad you restricted me to the scientific reason, Mimi. Otherwise I'd fill the whole column with tawdry rumors, and God knows you don't want that. More has been written about oversleeping in the medical journals than you might think.
Some people feel terrible after too much sleep, and their performance deteriorates.
On the other hand, 2. Some people feel great. Experiments seemed to bear out the initial hypothesis that either too much or too little sleep would cause your mental state to crumble. But by the early '80s a few investigators had concluded that 4. Oversleeping made people feel terrible if they'd previously had sufficient sleep, but it made them feel great if they'd previously been sleep deprived.