Lie, and you’re more likely to buy mouthwash.

Really: Being false leaves a bad taste in one’s mouth that is beyond figurative—and may also inspire altruism. After telling a lie, says the same article, you’re more likely to help others.

Maybe each of those instances is an act of compensation. A dirty thing came out of your mouth, so you clean it and scrub your conscience for good measure.

Even if you fool others, you’re never fooling yourself. A “tell” will arise, whether that’s a low moment or outright queasiness. Our brains are just bad with anything that feels fake. It’s a big part of why so many people hate networking and why your energy flagged after you said “let’s do lunch” to the former co-worker you’d rather roast over a spit.

(Emotion and sensation go both ways, though: Wash your hands afterward, and you may feel better about having said it.)

People want to feel good and to feel good about themselves. It’s what drives us to feed strays, buy cruelty-free shampoo, eschew that last cookie—or eat it.

All those actions, and so much advertising working to inspire them. Few of us are manipulative enough (or foolhardy enough) to build a call-to-action around making a person feel crappy about herself. And thus we probably won’t see a mouthwash campaign that pins all its hopes on inspiring people to lie to each other in droves.

There’s a basic version of the complicated circuitry of humanity, however. Even if we don’t totally understand the cause and effect in which emotion (and bugs in guts) seem to take the motivational lead, we know this: Lying feels shitty.

Lying feels shitty, and we feel shitty when we encounter it.

Makes perfect sense then that the advertising that works is the advertising that tells a recognizable, real story. Memorably, that has been the story of old ladies left wanting for hamburger, of stressed-out mofos needing a bubble bath, of the donut-maker’s exhausting dedication.

Of failure and legend.

Even if it ends up selling more soap, an inauthentic story will drive you to the shower yourself in an urge to wash away your sins.

Like many ads Nike has made, it does much more than build a brand. The company’s tagline alone hasn’t just increased signups for that office dodge ball team; it has also inspired massive lifestyle change. Like leaving the sumbitch, or moving cross-country, despite what might seem “common” sense.

Truth. You never know where you’re going to find it. That famous Nike tag was inspired by the last words of a murderer.

You know it when you feel it. And you realize you knew it all along.