“Are you sure?”
My dad taught me in second grade to always be sure of myself.

Back when I was in the second grade, my dad used to volunteer after school helping kids with math. I can only remember practicing with him once at school.
In second grade, I was doing math drills, answering each addition problem as it came up on a flash card, and one time out of the blue I got a pointed look, a raised eyebrow, and “Are you sure about that?”
I was right and I knew it, but still he hadn’t accepted my answer, so there was a problem somewhere. I checked and checked and examined every single step looking for my mistake. His face grew more and more smug until eventually I had no choice but to give up and ask for the right answer. I surrendered with a “yes, I’m sure” hoping he would tell me the answer and we could move on — but it turns out I had been right all along!
My second-grade self was absolutely shocked someone would ask me that question if I was, in fact, correct. From then on, I knew that trick, and usually immediately responded “yes I’m sure” for easy problems with easy answers — but the lesson it taught me is that I should always be sure of myself.
He taught me that it’s more valuable to 95% right and sure of yourself all the time*, than 100% right but crippled by self-doubt.
*later, I learned you also have to be able to re-evaluate those beliefs in light of new evidence…
