Sanity is not a requirement here 'bouts. Just ask Bernie...
"You are old, father William," the young man said,
And your hair has become very white;
And yet you incessantly stand on your head --
Do you think, at your age, it is right?"
"In my youth," father William replied to his son,
"I feared it would injure the brain;
But now that I'm perfectly sure I have none,
Why, I do it again and again."
-Lewis Carroll (1832-1898)