Shawn: Surprise! Surprise!
Shawn froze in shock as his Mom just laid out his biggest fear, plain as day - that he was a bad son, that he wasn't worth loving. And underneath the fear and the hurt, Shawn felt anger bubbling to the surface. It wasn't fair! He'd worked so hard to make her happy, done almost everything she asked of him, and it wasn't good enough for her!? But as soon as he realized that was how he was feeling, he pushed it away, crammed the anger deep down inside of him where it couldn't get out.
He wasn't making eye contact with his Mom, so he hoped she didn't see his weakness. He didn't want to cry in front of her - crying was selfish, it made things all about the crier, at least that's what he learned. So he just hung his head even more, hoping that she would stop, or at least explain how he could fix things.