Imagine you’re Paul McCartney. You’ve written (or co-written) 32 Billboard #1 songs. You’ve won 18 Grammies. You’re worth an estimated $1.2 billion. (Not that money is necessarily a true measure of success, but still.)

One of your songs, Yesterday, has been covered over 2,200 times by other artists.

And yet, when asked, here’s what you say about yourself:

“You never think you’re good. I really ought to think I’m fantastic because I have this pile of achievements… but I’m still going, “Oh, can I do it…?’

“I have a friend who’s a very famous orchestrator in the classical world and he says, ‘My biggest fear is being found out.’

“There’s a line in a song on my latest album, “Everybody else busy doing better than me.” I still think that way. I really do think that. I have to ague with myself and think, ‘That’s probably not true.'”

Yep. When asked how hard he is on himself, when asked whether he feels he’s “made it,” McCartney says he has always felt like a pretender — that, even after a lifetime of achievement, he’s afraid he’ll be exposed as a fraud.

And so do most of us.

One reason we feel that way is a phenomenon called imposter syndrome, the inner belief that you’re inadequate and mediocre — despite evidence that shows you’re highly skilled and very successful.

Valerie Young, the author of The Secret Thoughts of Successful Women: Why Capable People Suffer From the Imposter Syndrome and How to Thrive in Spite of It, identifies five sub-groups of “imposters”:

  1. The perfectionist. You set impossibly high goals for yourself, and when you fail to reach those goals, you don’t feel you measure up.
  2. The superwoman (or superman). You work incredibly hard because you feel you don’t measure up… and only by working harder than everyone else will you avoid being exposed for the fraud you think you are.
  3. The natural genius. You have a fixed mindset instead of a growth mindset, which means you assume success is based on talent, not effort — so if you have to work hard to achieve something, you doubt yourself.
  4. The rugged individualist. If you need to ask for help… you’re not as capable, skilled, and talented as you should be.
  5. The expert. Actually, you don’t feel like you’re an expert, even though other people may feel you are. You’re afraid you’ll be exposed as less smart, less experienced, or less talented than assumed.

Do any of those sound familiar? (Maybe not all the time, but certainly some of the time — because confidence is rarely absolute; confidence is almost always situational.)

Yet there is also another reason you feel you haven’t “made it.” You compare yourself not to how far you’ve come, but how far you still wish to go.

You ran a marathon… but you want to finish at the top of your age group. You’re a manager… but you want to be the CEO. You started a $10 million business… but you want to build a $100 million business.

What you’ve already accomplished? Unfortunately, you internalized those achievements long ago. To you, that’s just who you are. To you, your successes have become unremarkable and even insufficient — while to others, your successes are amazing and praise-worthy.

Imposter syndrome can be destructive, especially if it causes you to turn down opportunities due to fear of failure… or to step back when your true skills, talent, and experience means you are the perfect person to step forward… or to fail to reach your potential because it makes you wait for someone else to discover or select you.

Not feeling like you’ve made it? While it can be emotionally draining, that feeling is also what makes successful people become even more successful.

McCartney may have felt like a fraud during the heyday of the Beatles, but that feeling pushed him to write even better songs, to explore different styles of music… and to never stop learning, evolving, and trying to do better the next time.

And it can do the same for you.

Be glad you’ll probably never feel like you’ve made it, especially if that feeling drives you to put in the time and effort to turn “good enough” into great.. and then get up and do it again the next day.

Success isn’t a destination. Success is a journey.

Don’t hope to “arrive,” because that will mean your journey is over.

And where’s the fun in that?

You might also like: 

9 Phrases You Should Stop Saying if You Want to Be Happy and Successful

6 Incredibly Important Skills That Will Make You More Successful Over Time

How 8 Successful Business Leaders Unplug

Originally published at www.inc.com