Ha! No no, if I were looking for upbeat answers it'd be a bunch of responses saying "Nah, I'm awesome. Every day I know it."
I think it's easy to forget how much knowledge we've gained over the years through our experience. And too, it's difficult to quantify your true potential. Am I part of the top ten percentile? Top fifty? It's pretty vague.
It's probably best to remember that everyone brings their own skills to a project, like you say.
Thanks for responding!