We all have people in our lives we know are more damaging to us than beneficial. The difficulty, however, lies not in recognizing that certain people are toxic. It's knowing which ones we absolutely need to stay away from.

Here are the 5 most toxic people you need to avoid at work--otherwise you're in danger of doing yourself more harm than good.

1.The discouraging person.

There's always one person in the office with such a pessimistic outlook that there's no way to talk with them without coming out of the conversation sadder--and feeling worse about yourself--than when you began. Avoid this person every chance you get. You don't need that kind of negative energy in your life when there's already so much bad in the world.

2. The person who can't stop talking.

While chatter can be good for building relationships, there's something to be said about knowing when to stop talking and start being productive. Unless you absolutely have nothing to do at work, this person can be an uncontrollable drain on your efficiency. Try not to engage until you're sure you've accomplished enough to merit a break.

3. The person you're always competing with.

Even though it's natural to compete with those doing similar things, we have to make sure that our competition doesn't reach unhealthy levels. Take a break from the person you're always butting heads with to see who can do better--and know that, sometimes, just what you've done is more than enough.

4. The one who's always complaining.

This is the person who, while not necessarily negative, is always lamenting every task that they're given or assigned to do. Make sure that this person doesn't taint any job that you have to do with their off-putting words. That way, you might be able to actually enjoy the work that you're doing.

5. The one who doesn't listen to you. At all.

We all know this person--it's the one that you have to repeat deadlines, instructions, and details to five times before the task actually gets done. If possible, try to have other people in the office work with this character to save you the time--and exasperation--that will inevitably accompany any interaction.