Have you ever stood in front of the mirror and just not been satisfied? Maybe you're having a bad hair day. Maybe you've got a massive pimple. Maybe your favorite outfit is at the cleaners or you overindulged the night before and your face is showing it. Whatever the reason, did you tell yourself 'I'm just being vain. Appearances aren't really that important'?

While you were probably right from a moral perspective (judging people by their appearance remains a crappy thing to do), apparently from a scientific one, you were pretty much dead wrong. New research out of Stanford shows that appearances have an outsize effect on our behavior. That bad hair day actually matters.

Don't give yourself a mental demotion

To investigate the impact of not looking our best on our behavior, Stanford professor Margaret Neale and PhD student Peter Belmi asked a group of both women and men to write about a time they felt either attractive or unattractive and then quizzed them on their attitudes to inequality and hierarchy. The bottom line: feeling beautiful makes us feel powerful, and justified in our power.

"If you believe you are attractive, you tend to think you belong in a higher social class yourself and believe, accordingly, that hierarchies are a legitimate way for organizing people and groups. You also are more likely to believe people lower down in a hierarchy are there because they deserve to be," reports Insights by Stanford Business.

Your first reaction might be, 'wait, I learned that in middle school. Those that feel pretty really aren't generally the nicest folks in 7th grade.' And it's true that these results suggest putting your best foot forward in terms of your appearance might not do wonders for your kindness levels. It's probably worth reminding yourself of that when you're strutting out the door with your fabulous new haircut or freshly honed gym body to go interact with the world.

But it's also important to think about these results from the perspective not of those who feel particularly attractive, but of those that are suffering through that bad hair day. The findings suggest unruly curls or dark eye circles might not just be an insult to your vanity. They might cause you to mentally demote yourself down the social ranking. That really can't be good for your confidence levels or your professional demeanor.

A practical suggestion

To perform at your best, it's important to carry yourself like a person who feels like they look their best. One conclusion might be that when you need to come off as powerful, it's worth spending a little more effort on your appearance -- at least if you're personally not satisfied with it. But Neale offers a practical takeaway from the research which doesn't involve a trip to the stylist or clothing shop.

"Next time you're facing a situation that calls for you to present yourself in the best light--and perhaps a few notches up on the organizational ladder from where you normally perceive yourself to be--you might try a new strategy," Insights at Stanford reports her suggesting. "Just before the meeting or interview, remember a time when you felt attractive, and then let that memory change how you interact with others by reframing what you see as your place in the social hierarchy."