Simon said, "I struggle with the believability..." and "It just didn't feel authentic...."
Kara said, "When you're singing it, I don't always believe it. I don't know whether it's because you want to be perfect and you want to hit the notes... but you need to let loose and get out of that comfort zone of yours."
I think she hit the nail on the head. When John Park sang the song, he was so focused on getting it right that he failed to connect emotionally with the song and with the audience.
How often do you find yourself, as a speaker, stressed out because you're afraid of forgetting something or not doing everything exactly as you've planned and rehearsed it?
The more you try to memorize your presentation and make it perfect, the farther away you get from being honest (as John Park said he wanted to be) and authentic. The reason for this is that there's no such thing as perfect. We're all human. No one is perfect. So in striving to be perfect, you end up obscuring your true, authentic self under a mechanical performance.
Audiences don't care about perfection. They don't expect it. They want to relate to you, laugh, cry, be surprised, get goosebumps and feel something when you speak. If you don't feel it, how do you expect them to feel it?
Reveal yourself by getting out of your comfort zone. Stop playing it safe. Be vulnerable. Take a risk. Make a mistake. Make connecting with your passion and connecting with your audience the priority, instead of obsessing about getting everything right.
Perfection is the enemy. Resist!