One day, a scuba diver was out diving out in the ocean, leisurely propelling himself along with his fins about 10 metres down.
Looking around him, he noticed a man who was swimming at the same depth, but the man was without any scuba gear on, not even a mask or fins.
To show the man how amazing it was to be able to scuba dive, the diver decided to go down another 10 metres.
So he turned and went down to 20 metres, looked around and lo and behold, there was the same man, still swimming away.
“I can’t believe it”, the scuba diver thought, “I bet he can’t go down any deeper”, so he dived down another 10 metres only to find that the man was still there, swimming away!
Totally amazed by this, the scuba diver pulled out a chalkboard and wrote: “How the heck are you able to go so deep and stay under so long without any equipment?”
The man grabbed the chalkboard and wrote, “I’m drowning you moron!”
Image used under a Collective Commons License from https://pxhere.com/en/photo/1344539