• Spencer Rascoff is the CEO of Zillow, a real-estate website and app.
  • Rascoff says his wife always realizes he's unhappy at work before he does, and that helps him make his next career decision.
  • He calls his wife his "career mirror," and says everyone should have one if they want to be successful.

It can be hard to admit you're unhappy at work — even if you're only admitting it to yourself. Plowing ahead with your daily routine is in many ways easier than stopping and realizing: Hey, I'm miserable here.

So it helps to have someone who knows you well enough to do that work for you — to make note of your unhappiness and bring it to your attention when you're either too preoccupied or too much in denial.

Spencer Rascoff calls this person your "career mirror."

Rascoff is the CEO of Zillow, a real-estate website and app. Rascoff has had multiple careers: Before starting Zillow, he founded and ran the travel website Hotwire; before that, he worked in finance.

On an episode of Business Insider's podcast, "Success! How I Did It," Rascoff told Business Insider US editor-in-chief that his wife has always been his career mirror. He explained why everyone should have a career mirror in their lives:

"I think it's incredibly important for everyone to have a career mirror. It can be a spouse, a friend, a parent, but it has to be somebody that's far enough away from you that they're not in the super day-to-day — like it can't really be a coworker — but they have to be close enough to know you better than you know yourself.

"Every career decision I've made has been because my wife told me to, because she's held up a mirror to me. She said: 'Look, you're unhappy. You may not realize it, but you're unhappy doing this thing.' And when I left Goldman Sachs to go to private equity, and I left private equity to do a startup, when I left that startup to do another startup, every one of those career changes was because she saw something before I did about how I was feeling."

On some level, what Rascoff is describing is a person who's super emotionally intelligent. Empathy – which involves being sensitive to other people's needs and feelings — is a key component of emotional intelligence, according to the psychologist Daniel Goleman, who popularized the term "emotional intelligence."

Then again, another component of emotional intelligence is self-awareness, or the ability to realize that you're feeling a certain way and why.

Your best bet is to work on developing your self-awareness and to find someone who's sensitive to the fluctuations in your feelings. Consider a career mirror a sort of "backup" for when your self-sensors aren't working at full capacity.

With your career mirror's help, you can work on finding and creating a uniquely fulfilling professional life.