Think about the toughest person you know. What makes them tough? Are they physically strong? Are they able to deal with a lot of stress without showing emotion? Or do they know how to get what they want, no matter what the odds?

When I was in the military, we thought of “toughness” as a purely physical characteristic—how well we could handle physical demands and keep going, despite the challenges. But as I’ve moved through the various phases of my life—as a cadet, a diver, a husband, a father, and a business owner—I’ve redefined the word. I’ve watched those around me build businesses and families, and I’ve noticed that the difference between success and failure seems to come down to one, simple skill: the ability to take punishment and keep your original intentions. That’s how I define “toughness.”

If you’re a parent, think about your goals. Likely, you want to raise a healthy, happy child, guiding them with as much love, patience, and compassion as you can. But what about those long nights of teething and ear infections? The days when you can hardly keep your eyes open? Do you still manage to crawl out of bed when you’re needed and spend the night cradling and soothing your child?

Maybe you’re a business owner. If you are, you probably have a mission statement and a long-term vision for your company. But every business has its own challenges. Whether you’re experiencing an unexpected financial issue, a supply shortage, or a customer service complaint, how you handle it is often the factor that determines the outcome. Do you stay true to your mission statement? Do you continue working toward that ultimate vision?

True “toughness” is shown by the parent who makes it through stomach bugs and teething and still provides all the love and comfort their child needs, night after night. It’s demonstrated by the business owner who, in the face of a customer complaint, keeps their overall goal in mind and addresses the complaint in a calm, respectful manner.

As I write in my book, Toughen Up!, “a truly tough person is gentle and caring most of the time but knows how to stand up for something, overcome challenges as needed, and keep doing his or her best even when the odds are overwhelming.”

Remember, a positive attitude can be the difference between success and failure. If you stay positive and stick to your beliefs and your goals, good things will start to happen for you. If you let the challenges bog you down, your attitude will suffer—and you’ll lose focus on your vision. Positivity keeps you on track, while helping you defeat challenges and obstacles in a way that leave your integrity, your confidence, and your mission intact.

Over the coming months, I’ll be writing more about what it means to stay tough as you navigate life’s ups and downs. Have you had a recent challenge? What did you do to toughen up?