It is easy to dismiss the idea when it is new, when it is in inception stage, when no one has talked about it. Almost everyone behaves as a skeptic.
Bill Gates once said "Be nice to nerds. Chances are you'll end up working for one". Well that was just an idea then. Businessmen were supposed to be dressed in suits settling business deals in their cabins. If you were a small guy sitting in a small garage, you were told, you would never make it.
Today people who are drop outs, do not care for any kind of dressing, who think totally different from the world are making the waves. It is easy to dismiss them too unless you see that a 23 year old is a millionaire or a 16 year old is a phenomenal success.
Ideas have an ambiguity. One never knows if they are the one unless they become the one. And then the skepticism gets louder till the idea holds the skeptical public in its awe. That is why when we tell our thoughts to someone else, we are informed of doubts first and possibility later.
Once I was in discussion with a gentleman who told me sarcastically,
"Facebook is just a fad". I asked him "how did you know?". "I heard from someone".
Well that is the fad, I am talking about. That is thing that holds someone back from trying something different. That fictitious someone just killed the idea in the mind.
So next time when you get that idea , do not think it is not going to work because someone told you so. It is your idea, it is unique to you. Work on it, research on it but never give it up. Who knows you might be starting a new Google.