I probably second guess myself most when it comes to qualifications.

I do as well. I'll want to say something, then feel the need to preface it, start to, then stop, then doubt my doubt, and then my whole judgment is swallowed up. I have realized that my fence-jumping, my uncertainty with what I have to say, is really an imposition on whoever is listening to me to be patient. Be patient because I want to think this thought through out loud. It's tedious. What's more, I've learned that the anxiety of being misunderstood is a bit of an insecurity and I should trust the listener. If I was misunderstood, it's not the end of the world, I can add-on later to help the listener suss my meaning out. That's why this paragraph from Pinker, the author here, really struck me:

For all its directness, classic style remains a pretense, an imposture, a stance. Even scientists, with their commitment to seeing the world as it is, are a bit postmodern. They recognize that it’s hard to know the truth, that the world doesn’t just reveal itself to us, that we understand the world through our theories and constructs, which are not pictures but abstract propositions, and that our ways of understanding the world must constantly be scrutinized for hidden biases. It’s just that good writers don’t flaunt that anxiety in every passage they write; they artfully conceal it for clarity’s sake.