I know what you mean, I for sure got one of those opportunities I still think about.... All the time.
Three years ago I started my own marketing company, I had a unique idea and was the first to try to implant this idea. Sadly I got delayed 3-4 months so instead of being the first company to provide this service I was the the 2-3. Because of that the company only lasted 2 years when it could of lasted 4-5 and would of brought in x2 the money per year.
I learned from my mistake and if I have a unique idea like that again ill be prepared.