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No one has more nemeses than the writer Roxane Gay. Since 2011, she has tweeted blind items about various foes in a stream of captivating updates. “All last night, I visualized crushing my nemesis this weekend,” she tweeted in 2013. “My nemesis is having a good year professionally and has clear skin. It’s a lot to take,” she noted last summer.

Gay’s anonymous nemeses have become so well known that on Friday, Monica Lewinsky declared she would be dressing up as one for Halloween. “Not that i know who it is … just, ya know, generic nemesis costume,” she tweeted.

While having an opponent is nothing new, the nebulous concept of having a secret digital adversary is a more modern condition. Broadcast-based social-media platforms like Facebook, Instagram, and Twitter have allowed everyone to have real-time updates on other people’s biggest accomplishments, and that can make it feel as if everyone on the planet is getting married, writing a book, or winning an award. It’s easy, when you see someone leading a seemingly perfect life, to want to tear that person down.

As a result, the term nemesis is having a cultural moment. Claire Fallon of HuffPost declared a “nemesis Twitter” phenomenon. More than 260,000 posts on Instagram include the hashtag #nemesis. And high-profile YouTubers have generated billions of views by declaring feuds and then creating diss tracks against their digital competitors.

All these cases suggest that a nemesis is a special kind of foe. It’s not someone you hate with every inch of your being. That’s more of an enemy. A nemesis also isn’t a bully. A rival might be a fairer description, but a rival is someone you’re pitted against in a naturally adversarial environment, such as a sports game. Nemeses, meanwhile, are worthy foes in any area of life. They require a particular kind of jealousy, because you compete with them, even if they’re unaware of your existence. They can drive you mad with their achievements. But they can also push you to work harder.

In that latter respect, having a nemesis can be extremely valuable. “It rarely matters who is on your side; what matters is who is against you,” the writer Chuck Klosterman wrote in Esquire in 2007. “You don’t need a friend and you don’t need a lover. What you need is … one quality nemesis.” One 2014 study found that long-distance runners are about five seconds per kilometer faster when one of their top rivals is in the race. “Something about having an opponent gets us to dig deeper, into otherwise-untapped reserves,” the writer L. Jon Wertheim and the Tufts psychologist Sam Sommers declare in their book, This Is Your Brain on Sports.

The modern nemesis trend seems to be born partly from hater culture. On social media, everyone has an audience, so it’s easy for people to criticize you. They might root against you, or question your success, or troll in your mentions. Over the past few years, many people with large online followings have started encouraging fans to lean into these haters by using them as a form of motivation. As DJ Khaled would say, “they don’t want you to” succeed, so it’s up to you to prove “them” wrong. “Everybody have a Great Day,” Ice T recently tweeted. “Make your haters Sick.”

Declaring a nemesis can be a way to escape becoming a hater yourself. While hating is about putting others down, a nemesis is about pushing yourself to be better than that person. You still might relish in her failings, but ultimately you value your nemesis. You’d still show up to her funeral.

Two weeks ago, I selected a male journalist notorious for his relentless work ethic to be my nemesis. People kept mentioning his writing to me, and I suddenly felt the overwhelming desire to outdo him. Even a member of my own family—who will remain nameless to save this person some embarrassment—wondered whether I’d ever achieve as much as he has. Ever since, I’ve noticed myself working harder and putting in longer hours. Seeing my nemesis up at 7 a.m. on Twitter has made me more attentive in the morning. I’ve agreed to squeeze in more media appearances to talk about my work. Even though I might never reach his level of success, mentally competing against him has helped push me to do better.

Rachel Beckman, a multimedia artist in Baltimore, Maryland, has had the same experience. “I have a nemesis who works in a similar field,” she says. “Checking in on them really ups my confidence somehow. It’s a reminder that just because someone has more recognition doesn’t mean they’re better.” Alfred Wang, a writer in New York who loves break dancing, has benefited, too. He’s had a dance nemesis since the eighth grade. “We haven’t spoken in more than a decade, but I’m like, Oh, he’s getting pretty good; what if he’s coming for me?, and I started practicing harder,” Wang says.

Declaring the proper nemesis is key. Ideally you’ll find someone just slightly more successful than you are. You don’t want to be punching down. And it’s best to keep the name of your nemesis private. Running around talking trash about someone on the internet could lead to a very awkward encounter at a party or to getting reprimanded at work. Having multiple nemeses can be useful. You can have a work nemesis, a yoga nemesis, and more. They don’t have to be people you’ve ever met offline.

And remember to keep the competition positive. “[A nemesis] can be a healthy form of competition. It can make you step up your game,” says Bea Arthur, a licensed therapist and the founder of The Difference, a therapy service available on Amazon’s Alexa. “As long as you’re not actually hating or stalking them, it can be a good way to encourage you to pursue your goals.”

Not everyone will find a nemesis useful. Those who already struggle with self-esteem issues or jealousy can find having one unproductive. Jessica Wakeman, a freelance writer, realized several years ago that a one-sided competition she’d kept up for years was ultimately holding her back. Her nemesis “always seemed a level or two ahead of me,” Wakeman wrote in a story for Glamour. “No matter what I accomplished—a book review in The New York Times, interviews on TV—I felt like a failure in comparison … One of my biggest regrets is that I didn’t let my feelings go earlier.”

The journalist Eve Peyser wrote in Vice that having a nemesis was antithetical to her mission of being a kinder person on the internet. “Being an asshole online, whether it’s tagging the target of your wrath or subtly hinting at the identity of whoever you’re bashing, can make you seem unhinged and sickly,” she wrote.

There’s a possibility that some people rely on the concept of nemeses as a crutch. Jane Solomon, a lexicographer at Dictionary.com, notes that women can be chastised online for being too nakedly ambitious, so she speculates that some might adopt a nemesis as a way of expressing the things they want to achieve. “It’s not always socially acceptable to publicly articulate your own ambition,” she says. “It can be seen as wanting things that you shouldn’t want. Assigning a nemesis is an indirect way to talk about the things you want for yourself.”

Still, for many people, having that everyday opponent seems to provide a healthy outlet. I plan to keep mine, at least until I outdo him. Then, I’ll have to choose my next nemesis.

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