When my wife was a little kid, she would frequently exclaim, “I’m enough!” at the dinner table. Her parents never insisted that she ‘clean’ her plate. They’d say, “Stop eating when you’ve had enough,” and she heeded that advice. It’s a pretty straightforward concept, not eating when you’re full, but a difficult one to adhere to when you’re an adult.

I was thinking a lot about the concept this week – that we know we should stop eating, we know we’re full, but we still order the bread pudding regardless. I’m not as interested in why we do it (obviously, we derive pleasure from eating bread pudding), as I am in just how frequently we set ourselves up for failure in business and in life by not stopping when we’re enough.

Take poker or blackjack, for example. We rarely get up and leave the table when we’re ahead. We just sit there like a bunch of fryerim, or ‘suckers’ in Modern Hebrew, and eventually lose it all back to our opponents / the casino. Entrepreneurs are hard-wired as optimists, but we should still know better. If you have that mindset that screams “I’m in command of my situation,” and you’ve planned for this moment; if you know your strengths and weaknesses, and are honest with yourself, you’re much more likely to be able to walk away while you’re ahead. To win the cash. That’s discipline.

And we have to resist the same pull towards indiscipline to be successful in business as well, specifically in sales. After you close the deal, stop talking. If a prospect is turning into a customer right before your eyes, it’s time to yell “I’m enough!” internally, just as my wife did as a four year-old when she could only finish half of her corn on the cob. When your work is done, it’s done – have the discipline to know when you’ve accomplished what you set out to achieve.

If you’re already a great poker player, I can guarantee that you’re disciplined – you know your strengths, and your weaknesses. If you’re already a great negotiator or sales professional, your close rates are superb in part because you know when to exercise verbal self-discipline.

But for most of us, those still on the path to greatness, we can’t always rely on our incessant optimism (“my stomach won’t hurt this time, surely it will be OK,”). Most of the time, we’re better off being honest with ourselves, knowing our limitations, and exercising a bit of self-discipline. For me, that means passing on the bread pudding more often than not.