...that I'm not smart enough. Yes, I know - hard work matters more than smarts. But I look at kids way younger than I am who are building things and have had a natural scientific curiosity, making physics for fun, doing differential equations since they were 8, etc. And I can't help but feel mediocre. Especially since this newly founded ambition sprouted late. Imagine if I had begun way younger. Can hard work really beat talent? Were there any notable engineers that began later in life? As far as I know, most nurtured this interest early on in life. I would love to invent something incredible, but I think that I don't have the background for it. tl;dr: I love engineering, began late, fear that all the hard work in the world may not be enough to triumph over people who have been doing this stuff for years. Apologize if I sound naive, jealous, or overly conceited.