What Do You Think About While You Swim?

So, this guy with whom I swam a few times several months ago asked me, "What are you thinking about when you swim?"  I thought a few seconds and replied, "Nothing much."
"No, really, what do you think about?" he repeated.  Well, I thought longer about my time swimming and came up with, "Well, I used to think about getting eaten by sea monsters about every two minutes for a long time."  "What?" he asked.  "You know, I couldn't stop worrying about sharks, and I would obsess that I would get bitten by a big one every minute." 
"Oh, I don't worry about that," he said.  'Baloney,' I thought to myself.  Everybody has to think about that from time to time.  It's scary out there sometimes.  Actually, when I started swimming seriously in the ocean years ago, I DID obsess about sharks.  I couldn't STOP thinking about the imminent shark bite to the hip or thigh, truly every two minutes throughout my swims.  At home, I would quickly turn the channel on the TV when one of those frequent shark documentaries appeared. 
When I bumped into a clump of kelp abruptly on a swim, my heart would almost skip a beat as I scared myself half to death.  When I saw the flash of a dolphin, I would think "shark" first for an instant.  And harbor seals ducking and popping up nearby-they gave me a reason for fright. 
But back to his question.  After some years of swimming, I got more serious about the "swimming" part of the swim and less aware of the underlying "deadly sea life" aspect of the swim.  I studied up on the basics of the freestyle stroke.  Back in the day when I learned to swim and to be a swim instructor, I learned about the "reach, pull, and push" of the arm stroke.  I learned of the need for high elbows and rotation of the shoulder using the large muscles of the shoulder and back to decrease arm fatigue.
I learned that the body should lie horizontally in the water with the head looking forward while the water strikes the forehead.  That was proper body positioning for freestyle.
The legs would rest slightly below the surface of the water and when the flutter kick was done, the feet would break the water surface, aiding propulsion. 
I was taught about the body's "natural buoyancy," and I believe that this topic is the number one "most important" part of swimming and water safety.  I learned "Archimedes Principle," that the body HAS to float-well, provided that the lungs are not full of water, that is. 
And it's easier to float in salt water than fresh water, because the salt water is heavier, and thereby exerts a stronger buoyancy effect on the swimmer.
And breathing.  Is anything more critical to the success of the swimmer than the ability to breathe in a relaxed, effective manner.  Think about the rotation of the head to the side, not lifting the head to tire out the muscles of the neck and shoulders.
Well, to answer his question, these are the things that I think about now while I swim.  I'm trying to increase my efficiency and speed.  I'm trying to relax and make my stroke longer and more efficient.  And the kick-doggonit, the kick is such a difficult part of the swim, isn't it?  I think about that one a lot while I swim.
So, sharks be damned, and kelp-you don't scare me anymore.  I'm trying to swim, dammit, and I don't have time to be afraid of sea monsters.  How about you?