What's Missing?

Something is missing from this video? Can you tell what it is? Gabby started riding her bike without the training wheels tonight. My wonderful neighbor helped talk her into it and then helped her do it. It was pushed along by the fact that the training wheels are starting to bend under her weight and use. I knew she could do it but she has been scared to try. It helped to have someone else there so she couldn't get so mad at me. Cheryl was more patient than I probably would have been too! She's still working on turning and steering and keeping it going but she was doing pretty good for a first timer!