Okay, enough talking in riddles. What I'm referring to by my premise is that if in whatever profession you are in, be it programming, sales, marketing... if 100,000 people come up to you and say "Looks good. Love it! You did that? Great job!" we smile and continue about our day. Sometimes we will even dismiss it all together. "Ah... it was nothing." or "It wasn't me, they did all the work." But if 1 person approaches us and says our idea is dumb or that we failed, all of those praises fall by the wayside. We focus intently on the one negative and try to understand it. Why did they not agree with us? Why did they attack us? Is there something wrong with me?
Do not play victim to this. See the comment for what it is. Criticism based on someone's opinion. Don't let the voice of one drown out the echo of thousands. Believe in what you do and what you stand for.
One last note. More times than not, that one person criticizing your idea or calling you a failure might just in fact be the person in the mirror. Be your greatest cheerleader, not your worst critic!