I once went swimming in a friend’s pool. I swam to the bottom, and pulled my legs under me, trying to sit on the bottom of the pool for a moment. Opening my eyes, I looked around. For some unknown reason, I decided to take a breathe of air, as though I wasn’t sitting at the bottom of the pool. For a moment, I actually thought I was in open air. Instead of choking on water in my lungs, I ended up just swallowing a mouthful of chlorinated pool water, and realizing what I had just attempted to do.

I swam back up to the surface and got out of the pool.