Some books don’t just sit on your shelf; they stay in your mind even after you finish reading them. For me, ‘Can’t Hurt Me’ by David Goggins is one of those books.

A few months ago, I picked it up because many people said it was great. I thought it would be a normal motivational book with a few good lessons. But it turned out to be much more. It completely changed the way I think.

David Goggins doesn’t just talk about working hard; he actually lives it. He’s very honest and intense. Listening to him or reading his story feels like getting a strong energy boost. If motivation were a drink, this book would be the strongest black coffee ever, no sugar, no milk, just pure, powerful truth.

There’s one idea from the book that really surprised me: the 40% Rule.

Goggins says that when we feel like we can’t go any further, whether we’re tired, stressed, or ready to give up, we’ve actually only used about 40% of what we’re really capable of. That means we still have 60% left inside us!

At first, this was hard for me to believe. But the more I thought about it, the more I saw times in my life where I gave up too early, way before I ran out of energy or ability.

When I Look Back, I See Only My 40%

Sometimes when I look back at my work life, I feel a little sad. I started some projects but quit when they got hard. I avoided tough talks and told myself I was too tired. But deep down, I wasn’t. I just didn’t push myself enough.

If I had pushed just a bit more and reminded myself I had more to give, who knows what I could’ve done? This book made me see my excuses and habits clearly. It showed me that I often stop too early, when I still have more inside me.

A Mantra That Changed My Mindset

Now, whenever I feel stressed or really tired, I tell myself something that always helps:

“This is just my 40%.”

Whenever I feel lost or stressed about money or work, I repeat that one short sentence. It reminds me to stay calm and strong. It helps me focus and keep moving forward, even when things get tough or when I feel scared about what’s going to happen next.

When I’m leading my big team of more than 100 people, and I start feeling like I’m not good enough, I tell myself that line.

When I mess up or feel unsure, I say that line to myself. It helps me push forward. I’m not a superhero. I’ve just learned that I still have more to give, even when I feel tired or stuck, I might only be at 40%, not the end.

Growth Lives in Discomfort

Most people don’t like feeling uncomfortable because it’s hard. But Goggins says you can’t grow without it. Growth comes when things feel tough, not when everything is easy. If it’s uncomfortable, it probably means you’re getting stronger.

To get better at anything, you have to go through tough times. I once believed that feeling uncomfortable meant I was failing. I thought hard things weren’t meant for me. But I’ve learned that discomfort is part of learning, not a sign to quit or walk away.

But now I see things differently: feeling uncomfortable isn’t a warning to stop, it’s a signal to keep going.

It means I’m growing and getting better.

Now, every challenge I face reminds me that I’m learning. That I’m changing. That I’m becoming the person I’m supposed to be.

We All Have More Inside Us

The 40% Rule isn’t only for Navy SEALs or people who run long races. It’s meant for everyone.

Whether you’re someone starting a new business, a parent handling many things at the same time, an artist stuck without new ideas, or a leader trying to deal with a lot of problems, you have more strength inside you than you believe.

You just need to stop thinking that 40% is all you can do.

Because it’s not true.

Some books don’t just motivate you, they wake you up and make you think differently. Can’t Hurt Me by David Goggins is one of those powerful books. In this blog, I discuss how one big idea from the book, the 40% Rule, changed how I see challenges. Before reading the book, I thought if something was hard, it wasn’t meant for me. I believed discomfort was a bad thing. But now I understand that growing always feels a little uncomfortable. That’s how we learn and get stronger.r someone is chasing a dream, you have more strength in you than you think.

So ask yourself: are you stopping at 40%, or are you ready to find out what the other 60% looks like?