Too much self control - such a thing?

Is there such a thing as too much self control? Here is the story: Hudson is an energetic, yet emotional boy. Lately he has become self conscious of people watching him, mainly when he is doing something new, or he thinks people are going to laugh at him. So for his 1st school spring program we talked to him about having self control on stage. Basically, don't flip out while your standing in front of everyone and know that everyone else is looking at their kids. So when he got on stage he just folded his arms and barely sang. I must say I was disappointed and his teacher couldn't believe it. They said he usually is such a "show man". At least he had self control and didn't let his emotions get the best of him and for that he got ice cream. :)