Insecurity can show up in a workplace in many forms, including defensiveness, rudeness, hostility, jealousy and an inability to handle criticism. Insecure colleagues might also be overly territorial and quick to blame others, and exhibit an excessive need to compete. Working with insecure colleagues -- especially if they are supervisors -- can stress you out and interfere with your productivity. The best way to deal with insecure colleagues is to take steps to better understand their behavior.
The words and actions of an insecure colleague can be so upsetting that you are tempted to strike back -- but don't. It will only make you look bad and give him more of an excuse to be hostile toward you. Remind yourself that the colleague's behavior is likely rooted in feeling badly about himself. It helps to try to understand his motivations instead of getting angry. Calmly ask him why he is upset with you and pay close attention to his answer so you have more insight into why is insecure.
If you have made a mistake at work that has a negative effect on your insecure colleague, it is helpful to acknowledge the error and apologize for it. This can provide an automatic boost to someone who is insecure. Being honest about what you could have done better levels the playing field and makes you seem more human in the insecure colleague's eyes, winning her trust.
If your insecure colleague has done a good job on a project with you, compliment him on it. Share the limelight with him when your boss or other team members give you recognition for a job well done. Giving credit where it is due helps your insecure colleague feel good about his contribution and satisfied enough to not try to sabotage your own efforts or be overly competitive.
Find Something Positive
It can disarm your insecure colleague if you compliment her, especially at times when it would be easy to criticize her instead. Focus on at least several positive traits that your co-worker possesses, or something positive that she contributed, so that when her insecure behavior surfaces you can tame it before it has a chance to escalate. Honest compliments also serve to boost your colleague's self-esteem so she is less likely to act defensively.