When I was 10 I saw a made for TV movie about a boy who accidentally cloned himself. The clone learned quickly, but I thought "wouldn't he have to teach the clone how to pee and take a shower?" So, I imagined how that would play out.
Yeah, it was all downhill from there. I'm surprised I don't have a water-sports fixation.
I should note that I was very sheltered, and it would be 3 years before I discovered what I was doing was called.