What If Megalodon Sharks Never Went Extinct?

Would you ever venture into the ocean if you knew this creature could be lurking beneath you? It's twice the size of a T. rex, its jaws are big enough to crush cars, and it can swallow multiple humans at a time! This ancient beast is called a megalodon shark, and if it had never become extinct, it would have a surprisingly large impact on our lives. How would they change the way we use our oceans?