It's unquestionable that you need energy, excitement and confidence to be good at something. Anything from being a doctor, lawyer to professional athlete.
So let's clarify these words before we start the strawmen arguments of "So lawyers should be jumping for joy and act like Billy Mays in the courtroom, right columbo?"
Energetic (Possessing, exerting, or displaying energy.) - You need to have energy about what you do. Stephen King is energetic about writing horror fiction. He doesn't high-five everyone around him but you can tell he puts his energy into his books.
Excitement (A feeling of great enthusiasm and eagerness) - What you do needs to excite you. It should be something that keeps you up at night thinking about it. A good surgeon should be excited to learn about new techniques and discoveries in his field.
Confidence (a feeling or consciousness of one's powers or of reliance on one's circumstances) - You absolutely must know that you are going to sink that next basket. You don't need to walk around like you're the best person at the game but you need to believe that you yourself have the ability.
So yes, you need these traits to excel. To argue this is really just leading towards a debate of "Well I choose a narrow definition of excitement and since doctors aren't that then it is irrelevant".
Projection (The act of projecting or the condition of being projected.) is going to be the only thing people can fall back on. I don't believe they are saying to fake some part, but it definitely is not what I'm saying. Having these traits leads to projecting these traits. Your excitement, confidence and energy comes out when you talk about what you love to do. It just does.