What is the worst swimming-related experience you have ever had?

Used to live at Venice beach in LA. One day after running a few miles along the beach, I decided to go for a swim in the very cold ocean to cool down (I was not a regular swimmer in those days). There had been a very big storm the day before and the breakers were in the six foot range. Got out beyond the breakers OK and swam around for a while, but started to get real tired and leg cramps so decided to head back to shore. I got within about 100 feet of the shore and got stuck right where the waves were breaking in about 8 feet of water. Waves were coming fast so every few seconds I would have to turn and dive into a wave to avoid getting slammed and then try to make a little forward progress before the next one, but rip current was preventing me from going anywhere. I quickly realized that I was in trouble, so had to yell for help, which was very embarrassing. Not many people around but someone finally saw me and went looking for help. But I was so tired by then I knew I couldn't make it until help arrived. So I looked for a really big wave and with my last remaining strength, I was somehow able to body surf it just far enough to get my feet on the ground. Then I dragged myself the remaining 50 feet or so to shore and collapsed. I didn't completely lose consciousness but was very close. The lifeguards arrived shortly and they had to take me home in their dune buggy. I was pretty much a vegetable the rest of the day, but fine the next day. I've had a lot more respect for the ocean ever since.

Used to live at Venice beach in LA. One day after running a few miles along the beach, I decided to go for a swim in the very cold ocean to cool down (I was not a regular swimmer in those days). There had been a very big storm the day before and the breakers were in the six foot range. Got out beyond the breakers OK and swam around for a while, but started to get real tired and leg cramps so decided to head back to shore. I got within about 100 feet of the shore and got stuck right where the waves were breaking in about 8 feet of water. Waves were coming fast so every few seconds I would have to turn and dive into a wave to avoid getting slammed and then try to make a little forward progress before the next one, but rip current was preventing me from going anywhere. I quickly realized that I was in trouble, so had to yell for help, which was very embarrassing. Not many people around but someone finally saw me and went looking for help. But I was so tired by then I knew I couldn't make it until help arrived. So I looked for a really big wave and with my last remaining strength, I was somehow able to body surf it just far enough to get my feet on the ground. Then I dragged myself the remaining 50 feet or so to shore and collapsed. I didn't completely lose consciousness but was very close. The lifeguards arrived shortly and they had to take me home in their dune buggy. I was pretty much a vegetable the rest of the day, but fine the next day. I've had a lot more respect for the ocean ever since.