Control your urge for revenge to avoid escalating things.

Get comfortable apologizing to others.
When you’re dealing with someone you’ve offended, simply apologize for your actions. You can simply say, “I’m sorry, that was my fault.” If a customer walks into your shop annoyed about something someone else did to them, say “I’m sorry, these things happen.” This can minimize the chances of the person continuing the cycle of revenge on others.

Write a letter instead of seeking revenge.
For example, if a customer service agent has annoyed you, write down your frustrations in a letter and post it on an online forum. You can do this anonymously and even change the names of the people/companies involved. This can be incredibly therapeutic, and helps you direct your frustration towards the people who have the power to change things, rather than the lower-level staff you interact with.

Vent to close friends or family members.
Talk to someone you trust about how you feel about your experience. This allows you to release your pent-up emotions so that you no longer feel the urge to revenge against the person who offended you.