I love the way confidence plays into things. I run alone, I race seldom (like once a year), and I have relatively little knowledge of the "culture" of running. Going to the Houston Marathon, including something as simple as the Expo, is intimidating.
For example, these people look fit! They are thin, they look ready, and they really look like they know what they are doing. If not, why are they here at the start of the Houston Marathon in the first wave within easy sight of the starting line? I can't stay with these guys! Get me out of here!
But wait, what's that about a Drugstore Cowboy? You can dress the part but it won't get you to the finish line any faster. So maybe my shorts are the right length after all. Maybe my gray socks will be fast and get me to the finish line. Maybe I don't need Nikes and my New Balances are really good enough. Maybe I've trained more and harder than almost anybody. Maybe, maybe.
It's not in the looks. It's in the preparation, training, mental toughness, and willingness to push the limits. You do that, we'll be together on the course.