Chelsea Handler is the author of five New York Times best-selling books.

She runs her own company, Borderline Amazing Productions, and makes a multi-million dollar living as a woman in comedy, an industry dominated by men.

In 2012, she made Time Magazine’s list of Most Influential People, and she has also been on Forbes’ Celebrity 100 list.

She is, by all accounts, extremely successful.

But she didn’t start out that way. She wasn’t born with a silver spoon in her mouth; in fact, her first job was as a waitress, where she brought spoons to others.

It was during that waitressing gig at 23 years old that she learned a lesson that would serve her for the rest of her career, and what she passes along now as her best career advice:

“When you make a commitment, keep it.”

Handler says that that while she was never the best waitress, she was “always the person people called when they needed a shift covered because I would always say yes … [W]hether it was wanting to be dependable and reliable after years of being the opposite, I just wanted people to feel that they could count on me.”

Interestingly, this ended up impacting more than just her colleagues; it increased her own sense of self-worth:

“I didn’t want to work the extra shifts. There were times I would tell the person asking ‘I don’t want to work on a Saturday night, but if you really want it off, I will do it.’ That gave me a sense of worth and reliability. It gave me something more inspirational to do than just going to work every day and trying to remember the monotony of the menu and the goddamned daily specials.”

It also affected her career. “[M]y habit for reliability bled into my stand-up vocation. I kept showing up. When there were only two people in the audience, I showed up and did 10 minutes of material … (It turns out that if you can make two people laugh, then you can make two thousand people laugh).”

Now, she says, showing up has “permeated every facet of my life. Whether it’s wanting to cancel a workout, a friend’s party, a public appearance, my family in New Jersey. Whatever it is, when I commit, I show up.”

Let’s face it: It is common, whether in your personal life or professional life, to flake out. We all do it. Whether for a project at work or coffee with a friend, it’s easy to let things slide–especially when you’re tired, overtaxed, or overworked. How many times have you told someone you’ll email them tomorrow, only push it off to the day after?

Yet something is lost when you do that. Not only to the people who learn that they can’t always depend on you, but to you — your self-esteem, self-worth, even your purpose.

Conversely, the opposite is true.

When you show up, you feel a sense of pride. You start to know that even if you have to take two subways to get there, or sit in rush-hour traffic, if you said you’d go to your friend’s play, you’re going. Period. You don’t have to vacillate back and forth, weighing pros and cons, or spend energy composing the perfect, polite text begging off. If you said you’d go, you spend energy getting there, instead of deciding whether to go anymore.

Yes, sometimes this means you’ll feel tired and annoyed and wish you were watching Netflix. But fundamentally (and especially over time), when you consistently follow through, you become different. You stand up straighter. You feel your feet more solidly on the ground. You know you can be depended on. By your loved ones. By your coworkers. By yourself.

So if you want to take some advice from a millionaire who does what she loves for work, try this on for size:

When you make a commitment, keep it.

Then watch things flourish.

Originally published at www.inc.com