[johnsang]

Pretty much every single unicorn except for Amazon and perhaps Uber. eBay, AirBnB, Facebook, Twitter, Snapchat all seemed like strange ideas. Perhaps transformational businesses are supposed to sound totally nuts until you speak with the founders.

[troydavis]

Transformational businesses are nuts until someone executes fantastically well.

(Without the fallacy of the genius idea, this thread would be "Ask HN: What's the worst startup idea you've heard, which someone executed amazingly well?")