The ancient Stoics didn’t party like it was 19 or 99. These poker-faced philosophers from the Roman and Greek empires believed that happiness comes from living simply, accepting what you have, and not being controlled by desire or fear.

Central to their philosophy was this simple principle: You can’t control external events, but you can control how you respond to them. Translation: If you can’t accept the crap that life inevitably throws at you, you’ll be blindsided every time.

The Stoics would know—they were hit with a lot of crap. Epictetus, one of the most famous, was a slave in Rome. He finally found his freedom and started his own school, only to be banished from the city a few years later by a philosophy-hating emperor.

Seneca, meanwhile, was a tutor and advisor to Emperor Nero, which might have been a good gig if the less-than-stable ruler, in a fit of paranoia, hadn’t ordered the renowned thinker to take his own life. He complied by slicing his own veins and bleeding to death.

A third famous Stoic, Marcus Aurelius, may have been a Roman Emperor, but his consistent bad health and personal tragedy was, he wrote, proof enough that the only power you have is over your mind.

“Realize, this,” he advised, “and you will find strength.”

So, if appreciating life’s awesomeness means dealing openly with its bummers, how can we learn to suck it up and find true happiness? Here are three lessons in Stoicism you can apply today:

Lesson #1: Visualize the Negative

Want to build an attitude of gratitude? Then start imagining the worst. In his book, A Guide to the Good Life: The Ancient Art of Stoic Joy, William Irvine explains that thinking about how bad life could be allows us to appreciate how great it actually is.

Regularly practicing the Stoic art of “negative visualization,” Irvine says, expands our capacity to count our blessings and notice the beauty of everyday life. Just be careful: If you focus too obsessively on the negative, it’ll become harder to see the positive, which, of course, defeats the purpose.

Lesson#2: Delay Gratification

We all love modern conveniences. But if you find yourself cursing the slow-poke at the ATM machine, it’s time to reframe how you think about them.

The Stoics had a cure for such arrogance: Regularly deny yourself, so you’ll be delighted when stuff is available to you.

Seneca called this “the practice of poverty.” In a letter to a friend, he wrote, “Set aside a certain number of days during which you shall be content with the scantiest and cheapest fare, with coarse and rough dress, saying to yourself the while: Is this the condition that I feared?”

Can you go two days without checking your social media feeds? Live without wi-fi for a weekend? Go one week without ordering takeout? Of course you can. You’ll learn to appreciate these things more and strengthen your self-control along the way.

Lesson #3: Turn Every Obstacle Upside Down

“The impediment to action advances action,” Marcus Aurelius wrote. “What stands in the way becomes the way.”

In other words, when faced with a problem, change your perspective by deciding what really is an obstacle and what could be an opportunity.

Example: You lose out on a promotion to a less talented peer. Instead of confronting your boss or threatening to quit, you empathize and recognize—it was a tough decision for her, and a setback for you. But maybe you could instead focus on another grow opportunity for the company. Prove yourself there, and when your peer drops the ball, you’ll be poised to pick up the pieces.

By turning every problem upside down, you’re giving yourself a chance to turn something bad into something awesome—and therein lies the true path to happiness.

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