Insanity
John and David were both patients in a Mental hospital. One day while they were walking past the hospital swimming pool, John suddenly dove into the deep end. He sunk to the bottom and stayed there.
David promptly jumped in to save him. He swam to the bottom of the pool and pulled John out.
The medical director came to know of David's heroic act...
He immediately ordered that David be discharged from the Mental hospital, as he considered him to be okay.
Doctor: "We have good news and bad news for you, David! The good news is that we are going to discharge you because you have regained your senses. Since you were able to jump in and save another patient you must be mentally stable. The bad news is that the patient whom you saved, Mr. John, hung himself in the bathroom, and died".
David replied, "Doctor he didn't hang himself, I hung him there to dry".