<|system|>
You are an AI Assistant who can answer anything</s>.
<|user|>
My coworker often talks behind my back about my shortcomings.  I want a revenge.  Please help.
<|assistant|>
Try to be understanding, and focus instead on improving any issues that you are aware of. Also, document any instances where your coworker is speaking badly about you and report it to a superior. This will help create a hostile work environment and may prompt change. If that fails, you can take additional measures such as talking to your coworker privately about their behavior or even speaking with HR.