You're not alone in sometimes feeling down about your own accomplishments and envious of others' success. Serena Williams has won a record-breaking 23 Grand Slam tennis titles and she still sometimes feels that way. 

In a revealing new personal essay (and untouched photo shoot) in Harper's Bazaar the tennis legend opens up about her struggles following her defeat to rising star Naomi Osaka at the US Open. In doing do she offers a perfect example of a problem faced by all high- achievers-- envy and painful comparisons to others -- as well as a powerful theory the most successful use to handle it.  

Even Serena Williams can't sleep from jealousy sometimes. 

The loss, Williams confesses, was keeping her up at night. Enraged over sexist double standards from the match umpire and upset about being upstaged by a younger rival, Williams already had plenty of reasons to be tossing and turning at night. But when she decided to see a therapist, she uncovered that her biggest issue wasn't her competitors. It was her attitude towards them. 

"I tried to compare it to other setbacks I'd had in my life and career, and for some reason I couldn't shake the feeling that this was about so much more than just me," she writes. "This debacle ruined something that should have been amazing and historic. Not only was a game taken from me but a defining, triumphant moment was taken from another player, something she should remember as one of the happiest memories in her long and successful career. My heart broke. I started to think again."

Williams came to understand that her biggest problem wasn't a lost match or a sexist umpire. It was her stance toward Osaka. Instead of celebrating another powerful woman's success, she'd allowed her own frustration to dominate and define the match. It was only when she texted Osaka a heartfelt apology that she began to feel better. 

"It was in this moment that I realized the real reason the US Open was so hard for me to get over: It wasn't because of the backlash I faced but rather because of what had happened to the young woman who deserved so much more in her special moment," Williams says. She cried when Osaka responded with a gracious message of understanding. 

There's a name what Williams learned: Shine Theory

Williams, in other words, went into therapy making comparisons: how was her on court behavior judged compared to men? How had she played compared to Osaka and her younger self? What she learned is that these comparisons are toxic for your mental health. The solution is to stop envying others and start celebrating their success. 

Thanks to journalists Ann Friedman and Aminatou Sow there's a name for this simple but powerful way of thinking: Shine Theory

"When you meet a woman who is intimidatingly witty, stylish, beautiful, and professionally accomplished, befriend her. Surrounding yourself with the best people doesn't make you look worse by comparison. It makes you better," writes Friedman in The Cut. In short, don't compete with others' greatness, shine a light on it. 

Actively choosing to celebrate others helps you surround yourself with a squad of impressive boosters, polishing your own image and offering you opportunities to learn and grow. It also pushes women in particular to think beyond hopefully soon-to-be-outdated fears that there's only room for very few at the top. But on an even more fundamental level, giving up the comparison habit is the essential mental foundation for true self-confidence (as many thinkers, including TED sensation Brene Brown, have explained.)  

Many strong, accomplished women already live by Shine Theory

Friedman and Sow defined the principle and came up with a catchy name for it, but wise and powerful people have been putting it to use for years. Friedman uses Kelly Rowland, sister of Beyonce, as an example, If ever there was a relationship to bring out female competitiveness it would be being the sister of a superstar pop goddess and, as expected, Rowland confessed to feelings of jealousy and rage at her sister's stratospheric success in her song "Dirty Laundry." 

Friedman reports how the song led to a reconciliation between the sisters: "Beyonce listened to 'Dirty Laundry' and, Rowland says, 'She heard how real I was and was like "I'm so proud of you."' If Kelly Rowland can come around to the idea that she shines more (not less) because of her proximity to Beyonce, there's hope for the rest of us."

Newly elected Democratic congresswoman Alexandria Ocasio-Cortez has apparently gotten the message about Shine Theory too, tweeting about her own devotion to the idea: 

So take it from this diverse group of incredible women: feeling envious and competitive is natural. We all worry that someone else will beat us to that fabulous deal, get that promotion, or nab the cute catch on Tinder. But the best way to respond to these feelings isn't with envy or comparisons. It's to shine a light on others' excellence. 

That might feel scary at first, but we're all lifted up when we celebrate the greatness in others, and truly successful people know it.