In the business world, credibility is a powerful thing. It shows your boss, coworkers and clients what they can expect from you.

Credibility is based on trustworthiness, intelligence and competency. And overtime, credibility becomes your reputation. Your ability to influence others is directly dependent upon how credible you seem. It’s one of the most important factors that will determine how far you will go in your career and how successful you’ll become.

In addition, it will eventually be a reason why a client does or does not choose you.  Here are some credibility-killing actions that you should avoid like wildfire.

#1 Being a Know-It-All

There’s always that one person who acts like they know it all and can never be wrong. You’re going to come off as arrogant, conceited and self-important. An experienced client will see right through this and walk away.

Tip: Don’t try acting like you’re the smartest person in the room, even if you think you are. Many people won’t appreciate you boasting your knowledge. Try being more modest.

#2 Flat Out Lying

This is that simple rule your mother taught you. It’s not about morals or ethics, it’s just advice. When you get caught, and you most likely will, it will hurt your credibility. How can someone trust you when they know that you have a lie(s) under your sleeve?

This also goes with beginning a statement with, “In all honesty,” “Honestly,” or “To be honest.” It suggests that up until that point, you’ve been lying or have not been completely truthful.

#3 Mr. Feel Good

Props to you for being optimistic and keeping the air positive, but you better make sure that you are delivering that optimism. Don’t promise a whole bunch of stuff and not deliver. It will kill your reputation.

Tip: Only promise what you can deliver. Nothing less and nothing more. What you say is what your client will be expecting.

#4 Being Defensive

Have you ever tried telling someone that they’re being defensive and they say they’re not? They probably went right back to being defensive, overly sensitive and thinned-skinned.

Tip: Learn how to take criticism and conflict without it going straight to the heart. And don’t take it personally, try to learn from it. A client or employer won’t feel strongly about your ability to manage and make decisions.

#5 Repeatedly Interrupting  

It makes you look insecure AND disrespectful when you insert yourself into a conversation when someone else is speaking. A client probably won’t appreciate the interruption either. The absolute worst is when people finish other people’s sentences.

Tip: During meetings it can be hard to remember a new thought or idea while people are talking. Write down your thoughts so you don’t forget (and don’t interrupt.)

#6 Failure to Take Responsibility

Mistakes never help your credibility but putting the blame elsewhere is far worse. It’s always smarter to fess up than finger-point.

Having credibility is some serious stuff and YOU have control over it. It’s your reputation. Don’t take it lightly because it’s hard to earn and easy to destroy.