I tend to think that ideas are a dime a dozen, and actually doing it is what makes the difference - Boyer-Moore is one of the few counter-examples. But if you also had the idea... could it be that you're unusually smart?

The details of Boyer-Moore seem obvious to me, in that you bump into them in trying to get it working, even if you don't foresee them. They are like workshop improvements. Did you manage to implement a version of it, as a kid? Or is this another instance of showing that actually doing it is what counts?