1 negative vs. 9 positive: which would you believe?

Imagine you are walking down the street and 10 people are walking toward you. 9 of them say such sweet and positive things to you and 1 says something nasty. Which are you going to remember? Chances are the 1 negative will become a booming voice that shouts over the voices of the 9 others. So this is why we must choose if we will build someone up or break them down. And also, surround ourselves with people that will build us up instead of breaking up down.

I like this quote on the back of a Starbucks cup:

How many times have you been told you couldn't do something, and then said "I'll show you" and done it anyway? Not many of us have the courage to continue in a course of action when we have felt defeated so many times before.
One thing that I find most difficult to do is to sing in front of people. I love to sing! Especially singing to praise Jesus, but I have a hard time actually being on stage.
A former worship leader kind of ruined my confidence in that department. He probably didn't do it on purpose, but his actions spoke louder than his words and told me that I was not good enough. So I believed it, even though so many people have told me different. I've had multiple people compliment me, from sweet ladies in front of my in church that lean back and whisper "Honey your voice is so beautiful" to friends that tell me "You should be up there" every time a new female vocalist is brought on stage to sing.
I just smile and thank them for their kindness, but it doesn't go much farther. It's like there is something blocking their compliments from truly sinking in. Like that worship leader's actions are standing guard at the pass between my brain and my heart, not allowing anything positive to pass.
I'm not mad at anyone, just making an observation.
So badly I would like to get up on stage and sing like I know that I can. But when presented with the opportunity, it never seems to go according to plan. My nerves and that guy's actions get the better of me and I forget how to sing!

What would you like to do, but have allowed someone's negativity to get the better of you? Tell me that I am not alone in this!