This series examines the stories behind some of the best inspiring quotes of all time. Check out the full list: The Best Inspirational Quotes for 2018.

This is a story about good luck--and how people who've had a lot of good luck account for having gotten it.

Its main character is Ray Kroc, the controversial founder of McDonald's, who died 33 years ago this month.

Kroc was a resilient inventor who already had several careers (mostly in sales) and was 51 years old before he even thought about going into the restaurant business.

And, truth be told, it's still an open question whether he should truly be considered the "founder" of McDonald's. 

If you've seen the 2016 movie about his life--called, yes, The Founder, staring Michael Keaton as Kroc--the picture you'll likely have of Kroc is complicated; creative, visionary, driven to a fault, at times even cruel.

The movie doesn't get all the details right--from the first few pages of Kroc's 1976 autobiography, Grinding It Out, Kroc portrays some things differently. But if you're looking for inspiration, you could do a lot worse. 

But set that aside. The Kroc quote that drew me in for my annual list of the best inspirational quotes is his line about the role of luck in life. He seemed not to believe in it, saying: "Luck is a dividend of sweat. The more you sweat, the luckier you get."

Quick aside: While the quote is all over the internet, and thousands of people attribute it to Kroc, I can't actually find an original source that says when he said it. 

Plus, the sentiment has been attributed to others--Thomas Jefferson for example, put it this way: "I'm a great believer in luck, and I find the harder I work, the more I have of it."

But let's drive on anyway, especially as Kroc expressed other, similar sentiments. ("I have always believed that each man makes his own happiness and is responsible for his own problems," he wrote in the opening lines of Grinding It Out.)

Kroc has the kind of success story that has almost no foreshadowing in it. It was just resilience and continual, tireless effort that predicted his ultimate triumph.

Kroc spent 17 years selling paper cups, and then spent years pushing a quixotic product--a fast food milkshake mixer that could produce five or six shakes at a time.

One restaurant in America saw great success with it: the original McDonald's in California, and learning about that led Kroc on an improbable journey to expand the restaurant brand and ultimately run the company.

In the end, however, what Kroc created wasn't just a business or a brand but a symbol of America--one that was arguably as well-loved worldwide as the American flag.

I'm old enough to remember being a kid when the first McDonald's opened in Moscow. It was a huge deal--not because Soviet citizens wanted hamburgers, but because they wanted the chance to experience America.

Seriously, check out the video at the end of this article, and the length of the lines when it first opened in 1990.

The point is, none of this seemed preordained at the time. None of it seemed explainable.

The only way a guy like Ray Kroc could be that successful was a result of pure, dumb luck. Or, just perhaps--it was the result of working hard enough to have the chance to take advantage of some amazing opportunities.

The moral? Work hard. Keep your eyes open. Make your own luck.