1. Take dramatic, angry personal phone calls.

Sure, nasty calls happen. But that doesn’t mean you have to subject everyone else to your drama. The office is not a place to do battle with your kids or siblings. Keep your relationship issues outside of where others are working and can hear you. Take a break and go somewhere private, or better yet, save it until you get home.

2. Send emails you wouldn’t want your boss to see.

If you are considering sending something offensive, sloppy, or asinine, just don’t. In the wrong hands it might hurt the company’s reputation and your own. And never assume that your email (even your personal email on company wifi) is private. It isn’t.

3. Gossip about coworkers.

Whatever information you’re spreading won’t make anyone look as bad as you make yourself appear for being the nasty and uncaring messenger.

4. Spend hours on your social media.

You are being paid to be productive, not play candy crush or catch up with an old high school buddy. Unless it’s part of your job, your social media activities should be saved for lunch or break times. And even then, use your phone and stay off the company computers for personal activity.

5. Lie to make yourself look good.

Technology makes it easy to exaggerate your credentials. It also makes it easy to find out the truth. Small lies will hurt you in big ways and someone will always bring the truth to light.

6. Come into work when you’re very sick.

Your commitment to your job is admirable, but don’t prove that you’re a good worker by exposing the whole office to your flu. Work from home if you can, but don’t bring your germs into an otherwise healthy workplace.

7. Hit on your boss, colleague, or employee.

Office romances make for exciting television, but more often than not they lead to awkward situations and even lawsuits. Keep your dating to your off hours. Can’t find someone easily? Try Tinder.

8. Respond when you’re angry.

The only thing more stressful to your body than anger is the guilt and fear of repercussions for taking out your anger in the office. Find ways to take a break and control your anger so you act reasonably and professionally.

9. Interrupt.

When you interrupt, you not only frustrate the person you are talking to but you give them a negative impression of yourself. Learn to listen. You’ll gain admiration and respect.

10. Get too comfortable.

Certainly society has become more casual. People don’t dress up for work and are much more familiar in their conversation. That doesn’t mean that wearing sweats and cussing are acceptable office behavior. Consider the impression you make in your looks, attitude and actions. Don’t assume everyone thinks your performance is worth the trouble and irritation you cause.

11. Come in high or drunk.

If you really can’t wait until after work, or you got so wasted the night before that you’re still messed up, you likely have a serious problem with substances. Stop subjecting your colleagues to your addiction and get some help–you’re not hiding it as well as you think you are.

12. Wear too much perfume or cologne.

In an enclosed environment manufactured fragrance can be annoying to some but headache and hay fever inducing to others. Keep the environment fresh and neutral for everyone.

13. Play any sounds, music, or noise on your computer without headphones.

The workplace is an environment designed for thinking and productivity. Your cat videos or electronica may help you think better but will likely disturb your neighbors in a tight cubicle environment. Do everyone a favor and help maintain the quiet.

14. Disrupt people from their work.

Just because you aren’t focused on achievement and want to goof off doesn’t mean others have your same lack of work ethic. Respect their right to pursue advancement. Many people use headphones to signal that they are unavailable to chat because they are either listening to something important or they’re in the zone. Respect their space and send an email or wait until they take their headphones off.

15. Permanently Borrow.

Otherwise known as stealing, there is just no reason to take something that doesn’t belong to you. Your company doesn’t “owe” you anything for your work. You are compensated through your pay. If that isn’t enough, have a conversation with your boss about it rather than stealing from the office to make up for your cowardice.

16. Make your personal life the office focus.

Yes, you are a human being and that means feelings. But learning to control when and where those feelings are expressed is key. Not everyone wants to hear about the latest chapter in your rocky relationship drama. It may be worth mentioning to your boss if something serious happens, like a death in the family or a divorce. Otherwise, make sure you aren’t letting your feelings run you when you should be concentrating on the task at hand.

17. Bully or Harass.

If you struggle treating all people with kindness and respect, perhaps you should seek career development in a field where you can work by yourself. Avoid customer service jobs for sure. Harness your inner adult and remain calm, rational, and pleasant in order to get the problem solved.

18. Shut off the world.

Most work environments require interaction and isolation only irritates and demotivates the people around you. Find ways to engage and inform so people see you as a contributor.

19. Share sensitive information.

What happens at your office belongs in your office. Respect private information. If you’re unclear about the sensitive nature of the information, err on the side of confidential and you’ll be in good shape.

20. Create conspiracies.

When you instigate a disruption in a team atmosphere, you accomplish nothing but low morale and productivity. Be forthright with the team and work to solve problems instead of creating them.

Source:  https://www.inc.com/kevin-daum/25-things-you-should-never-do-at-work.html