I call this principle the law of 1000-100-10-1, or, more self-grandiosely, Aguzzi's Law (even if, according to the law itself, I hold no good reason to believe that I'm its discoverer). It goes as such:
If you have an idea that you think no one has ever had before, a thousand people have had it, a hundred have done it, ten have recorded it and one posted it online.
– Federico Aguzzi (and at least a thousand other authors)
You don't believe me? Try coming up with an idea, any idea – then search it on YouTube.
Yes, someone has already built a rocket-propelled fishtank. No, you're not a genius.