The moment I became a dot on the left was one of abject humiliation. As I write in my book, The Dot on the Left, I was sitting with my new classmates at the West Point Prep School when the school’s commandant put the classes’ SAT scores on a screen for all to see. There, alone on the far left, was a dot representing my rock-bottom math score: 310 out of 800.

My classmates didn’t know that dot was me, but they jeered and chuckled at the intellectual, 98-pound weakling who’d put up such a pathetic score. But the worst part was that, even while my face reddened and my muscles went taut, I had to join them in mocking myself so they wouldn’t know I was the guilty party.

That moment scarred me. Even today, I can still hear the laughter of the other cadets, still feel the overwhelming desire to disappear into a hole in the floor. But we all have pain and humiliation in our pasts; what separates leaders and success stories from failures is that leaders don’t let their scars define them. Instead, they use them.

My humiliation taught me two very important truths, truths that I took with me into the Army, leading men in combat, and that I carry with me still. The first: Never sit back and let events define you. I could’ve let that early failure define what I could do, but I chose to be proactive. Growth, opportunities, the risks that change everything—they come to people who aren’t passive, don’t accept the judgments of others as gospel, and who get up and make things happen. Want to change things? Get off your ass and start by changing the one thing you can control: yourself.

The second truth: Don’t get comfortable. No matter how much we try to maintain our edge, all of us have a tendency to become complacent after we enjoy some success. We pat ourselves on the back. Read our own reviews. Congratulate ourselves on how awesome we are. And that’s usually the time when we get the rug pulled out from under us by a competitor, bad luck, or our own laziness. As I wrote in my book, “Based on my experience as an enlisted soldier and even as an officer in charge of men in combat, I would argue that humiliation is a leader’s best friend. The fear of embarrassment keeps leaders sharp in their day-to-day affairs.”

Those moments when you felt ashamed, when you couldn’t meet people’s eyes, when you let the team down—don’t let them define you, but DO let them remind you. Great leaders don’t get complacent, lose their edge, or sit back on their heels. Humiliation makes us wise.