In the business world, your credibility is everything. It tells people whether they can count on you. It tells your customers, employees, bosses, and coworkers what they can expect from you. Whether they can trust you or not.

Over time, that becomes your reputation. It becomes one of the most important factors in determining how far you go in your career. How successful you'll become.

It's not rocket science, so let's not complicate things. Your credibility is largely a function of the perceived gap between what you say and what you do. If your actions match your words, you might go places. If they don't, look out below.

Credibility is a powerful thing, not just because it has so much impact on your future, but also because you have so much control over it. With rare exception, it's more or less in your hands. And here are the biggest pitfalls you need to avoid.

Having all the answers. Some people act like they know everything. They can never, ever be wrong. They just have to show how smart they are. Funny thing is, really smart, experienced people know how much they don't know. And those people will see right through you when you act like a know-it-all.

Overpromising and under-delivering. Remember Facebook's initial public offering, the most overhyped IPO in history? Look how that turned out. It was a complete disaster. Now Zuckerberg and company have to work that much harder to win back their credibility. It's okay for goals to be reasonably aggressive. But when you're making a commitment, make sure you do what you say you're going to do. Simple as that.

Flat out lying. We all occasionally have to spin, pivot, deflect, or redirect. That's fine. But for God's sake, never ever flat out lie. It's not about morals or ethics. It's purely pragmatic advice. When you get caught, and you will, it'll ruin your credibility. That's why none of us trust our politicians anymore.

Filling the air with feel good fluff. It's good to inspire people. And it's okay to be optimistic about the future. But if you're going to be Mr. Feel Good, then you'd better deliver. I can think of a whole string of CEOs who destroyed their reputations by spewing feel good fluff and failing to deliver. They're no longer CEOs. Starbucks CEO Howard Schultz, on the other hand, said he could turn the company around, even in a recession. And he did. That's credibility.

Trying to be something you're not. I see it all the time, all over Silicon Valley: people dressing, speaking, or acting like they're Steve Jobs or Barack Obama. If you're so uncomfortable in your own skin that you have to put on somebody else's, then folks will think you don't have much going on under the hood. It shows that you lack self-confidence. Be the genuine you, flaws and all. You can work on becoming the best version of you without trying to be something you're not.

Being too politically correct. Ever hear someone trying too hard to be politically correct? It's painful to listen to, like they have to parse and process every word to make sure they're not offending someone. It takes them forever to make a point. It comes out sounding choppy and disingenuous. It's far better to be genuine and straightforward than to sound like you're pandering and afraid to speak your mind.

Telling people what they want to hear. Some people are yes-men. They sugarcoat the truth and tell people what they think they want to hear. They're also slippery. They change their story based on whoever's in the room. Holding them accountable is like throwing darts at Jell-o. Those people have zero credibility. It may work in government bureaucracies, but not in well-run businesses.

Being condescending. If you talk down to people and treat them like children it doesn't reflect well on you for all sorts of reasons. First, people will think you're a jerk. And nobody trusts or wants to work with a jerk. Second, the only people that will respect you are the ones who don't get it, and those people rarely play decision-making roles. Makes sense, doesn't it?

Being defensive. Funny thing is, when you tell people they're being defensive, 9 times out of 10 they say they're not. Then they go right on being defensive, overly sensitive, or thin-skinned. If you can't take criticism or conflict, if you have trouble openly debating issues without taking it personally, nobody will trust your abilities to make solid decisions, manage, or lead.

Having no sense of humor or humility. One of the biggest mistakes leaders make is being full of themselves or self-important. It's generally a sign of immaturity and that hurts their credibility. With experience comes wisdom, and with wisdom comes the knowledge that the world doesn't revolve around you and you're not nearly as smart or important as you thought you were when you were younger. That's why humor and humility are such important leadership traits.

Look, credibility is serious stuff. It's your reputation. It follows you wherever you go. It's hard to build but easy to destroy. Don't take it for granted. If you've got some chronic issues, get to work on them now, before you do some things you can't undo.