I was 5 years old the first time I ran into this. I played piano and had a rehearsal to play at. I had my song memorized and was ready to go. Then a person who was to go up and play, about two people before me started crying and freaking out because she had to go up in front of everyone and play. The thought of that never occurred to me, but after listening to her freak out and not go up and play. It was now part of my psyche and had to be dealt with as I was about to go up. Well, I decided to go try and play anyways. I thought I did well and wondered why that person was able to affect me like that.