On importance You question the importance and value of your writing a lot. So much so that you want to give up on writing and keep to yourself. Head down. Mouth shut. Writing about nothing. That's fine—if you're so worried about being important in the first place. The two remedies to this mindset are either to provide amazing value in your writing, or to stop worrying about how "important" your writing is. For the hundreds of thousands (if not millions) of words that Benjamin Franklin wrote, how many of them are still important? They may still be a part of history, but even one of our greatest diplomats exists only as a fixture of history. Jefferson surely had a hand in many great pieces of writing, but history only remembers one of them as significant. So, what? Your articles are not changing the world. They might never. Your ideas are not novel and you're not hailed as a genius because of your words. Is that why you did it in the first place? Of course not. Keep writing, improving your skill, and creating ideas. Not in hopes that you go down in history as a Jefferson or a Hemingway—only in hopes that one day, you look back on your work and with resolve, say, "I wouldn't have had it any other way."
On questioning As Tommy says in Goodfellas, "I wonder about you sometimes, Henry. You may fold under questioning." The most powerful tool for breaking your assumptions down to first principles is to question them. You have to probe your own understanding to be honest with yourself, because that is what everyone else will do when they hear or see what you believe. Much like in a debate, you have to actively seek out the holes in your case that will lead to your defeat. You may fold under questioning, but fold when you're questioning yourself and not when the market itself makes you answer its demands. At the same time, you don't have to answer to every question. Some things you must be delusional about and believe in when nobody else does, and that requires a large amount of self-awareness to do. Even then, you could still find a way to answer many questions about why you have a steadfast belief in what you do. When someone comes bearing concerns and doubts, don't shoot the messenger—embrace them. You will be better for it even though their questions feel annoying in the moment.