I failed level 2 swim lessons because I refused to jump in because I'm afraid of heights. So much so that even jumping from the pool's edge is enough to freak me out ("Just pretend the surface is solid!" you say. Uh, I can see THE TOP OF THE INSTRUCTOR'S HEAD from here. I KNOW I'm gonna fall.) Rather pathetic, being the oldest in the class (almost as old as the instructors), and being the only kid who refuses to jump.
I failed level 1 for similar reasons, but when I retook it they didn't make anyone jump. Plus, I'd already begun to teach myself how to swim by then. It came to me in a dream... really. I had a dream that I was underwater and I paddled my arms forward and tada I was swimming! So I tried it at lessons and it worked!
Later on, a friend taught me how to dog paddle. Now I could keep my head above water and still swim!
My current way of swimming isn't an orthodox method by any means (move my arms in a breast stroke, keep my head above water like in a dog paddle, and do a frog kick with my legs), but at least I can get from point A to point B without drowning. I kept practicing on my own and eventually taught myself how to tread water.
I know how to do a side crawl stroke too (learned that first from watching Link swim in Ocarina of Time, then watching my 6th grade teacher do it at a pool party while she was racing one of her students.)