In the first 10 seconds after the insult take a deep breath and gather your thoughts. It is not necessary to respond to an opponent in a dispute reciprocate – it is foolish to think that the transfer of the dispute "to the person" will help to solve the problem. So no need to insult someone on a hot head, show that you are smarter and able to think clearly. In itself, this behavior is already present you in a more favorable light than your opponent. And allow you to buy some time for the decision whether to prepare a retaliatory strike or forget spoken words?
After the strong emotions subside, you will have to decide – do you want revenge? If Yes, revenge needs to be proportionate to the offense. Do not attempt to cause the man more pain, moderate your desire to wipe it off the face of the earth. A worthy response to an insult might be a serious statement or ambiguous joke. The desire for revenge should not push you to spread information regarding personal life, his past and especially on the libel and budding rumors.
Revenge is a dish best served cold. To answer one serious insult can be multiple, smaller ones. Besides, sometimes revenge is a great motivation. If you have offended a colleague, you can show your superiority by getting the attention of rival positions or generous bonuses. No need to retaliate by means of anonymous letters, and "snitching" to authorities is detrimental for your image as a worker, too. Much more fun will revenge via a fair fight.