Harry worked as a deep sea diving instructor. Today, he was taking three tourists out for a dive. There were sharks in these waters, so he wanted them to be extra-careful. Two of them were attentive and followed all his instructions. The third, Jerry, thought he knew everything. “I’ve been diving before, you know,” he said arrogantly, “I already know how to dive safely.” Soon, the four of them were in the water. However, just as Harry had feared, they soon came across a shark. Jerry had ignored the safety instructions, and started panicking. His breathing sped up and he started using more oxygen than normal. He got so confused that he started swimming in the wrong direction. Luckily, Harry noticed him in time. He grabbed Jerry and pulled him up to the surface of the water. Jerry was shaken up, and apologised to Harry for his foolishness.