When I was young, my parents enrolled us in swimming classes every summer. The first year we took beginner class even though we already knew how to swim. The following summers we took advanced classes.
I remember the instructor teaching us something that I think was called the 'jelly roll". It's where you pull your legs into your chest and allow yourself to float to the surface. It's in case you get disoriented beneath the water and don't know which way is up. I never thought i'd have use for it.
Years later I did a running somersault off the side of the swimming pool. The impact when I hit the water knocked the air out of my lungs and I became disoriented having kept spinning after entering it. I didn't know which way was to the surface. I did not panic though.. instead, without really thinking about it... I pulled my legs into my chest and remained calm while my body righted itself and started floating towards the surface using the 'jelly roll' technique i'd spent a few moments learning years before.
Sometimes the things we don't think we need to learn end up saving our lives. Had I panicked in the water, and not remembered that simple technique.. it's very possible I would have drowned that day. The lifeguard was busy flirting with someone and not paying attention to the water.