Photo by Alan Hardman on Unsplash

I’ve had some great experiences over the years.

They’ve included working in management for a nonprofit I loved, starting my own business, consulting for the Fortune 500, serving as an adviser to an amazing startup, and writing my first book.

Through it all, I’ve learned to see life as a giant school, where every day class is in session.

But some of the greatest lessons I’ve learned came in one of my first jobs…

…as a pizza delivery driver.

Yup, that’s right. It was 1995 and I was 17, with my whole future ahead of me. Who knew how much I’d learn in that year and a half, working at the pizza shop five minutes from my house?

Here are the top 6 lessons I learned delivering pizza:

1. You need to take control.

On the surface, this was a job that paid minimum wage. But I also received a gas reimbursement for every delivery. (Since I drove a small Subaru hatchback that was extremely good on gas, I actually profited from this arrangement.)

But the real value was in the tips.

By learning advantages like the quickest routes to various neighborhoods, the best times to work, and who the best tippers were, I earned more in one evening than my (non-delivering) peers could earn in a week.

Lesson: There’s nothing wrong with working for a set salary in a typical schedule. But in doing so, your earnings will always be limited.

I learned to look for ways to maximize earning potential. This later led me to explore concepts like passive revenue streams, outsourcing work, and similar strategies.

2. The Pareto principle works.

Also known as the 80/20 rule, the Pareto principle states that 80 percent of the profit comes from 20 percent of the customers, working hours, etc. It’s why airlines do all they can to keep first- and business-class customers happy, despite the fact there are so few of them.

If you’ve ever worked in delivery, you learn to identify repeat customers–especially if they’re good tippers. So I’d study the store’s other drivers to see the patterns in their delivery runs, and learn the timing of how long it took the cooks to prepare an order.

Then, I’d take an extra delivery (or leave one behind) if it meant getting to a top tipper. I also learned the store’s most profitable hours and tried my best to get scheduled for those–in an attempt to make the most of my time.

Lesson: Profit isn’t just measured in dollars and cents–it’s also mentorship, experience, and doing work you enjoy.

Learn to use time and resources to your advantage, and you’ll make the most of what matters.

3. The benefits of hard work aren’t always immediately visible.

When no deliveries were ready, we drivers had to wash dishes. These weren’t just any dishes; they were dirty, greasy, batter-encrusted baskets–used to deep fry buffalo wings. We also had to mop the (extremely nasty) floor at the end of the night.

I hated those assignments, but Mom and Dad had taught me the value of working hard, regardless of the task at hand. Over the years (after moving on from pizza), I built a reputation for taking on tough assignments. But as I progressed to leadership positions throughout my career, I didn’t forget my lowly beginnings–and wasn’t afraid to get down and dirty.

Lesson: Work hard. Set the example. In time, people will notice–and follow your lead.

4. A good attitude goes a long way.

In addition to those awful dishes, my car smelled like food all the time. Not to mention, the hours killed my social life. (You can’t make money delivering pizza without working nights and weekends.)

But hey, I was a teenager and my job consisted of cruising around town, listening to my favorite tunes. Not to mention I got all-you-can eat pizza–for free. What more could you ask for?

Lesson: Happiness is an attitude, not a set of circumstances. If you’re going to do a job, focus on the positive and make the most of it.

5. Learn to track your money.

I was making bank as a delivery driver, but there were plenty of challenges. Those big tips meant more taxes deducted at the end of the year. I learned that if I didn’t plan my withholdings (and savings) well, I’d get into big trouble come tax time.

Years later, when I ventured off to start my own business, these lessons served me well. And although now I have a tax advisor, it helps to know how the principles work.

Lesson: Getting organized and balancing a budget are invaluable skills. Whether or not you work in finance, it’s important to understand how your company is managing money.

6. There’s more to people than meets the eye.

It’s easy to look at someone and think you know their story.

You don’t.

The people I had the privilege of working with included:

  • A guy who had won big bucks in the state lottery, but kept working anyway
  • A recovering drug addict, who turned out to be one of the smartest, most strategic thinkers I’ve ever met
  • A number of kind souls, each with unique situations, all struggling to make the most of their lives

As these people shared their personal narratives, I learned not to judge the book by its cover. And I benefited immensely from those relationships.

Lesson: Take the time to get to know people. Because you can learn something from everyone.

Parting thoughts.

At first glance, it’s easy to take the most humbling jobs for granted. Make sure you don’t.

Because if you look closely, the lessons are yours to learn.

Enjoy this post? Check out my book, EQ Applied, which uses fascinating research and compelling stories to illustrate what emotional intelligence looks like in everyday life.

A version of this article originally appeared on Inc.com.