I got petty revenge at work
What kind of revenge did you take?
I gave the worst coworker on my team more responsibility for a few days.
While that revenge doesn't seem that bad, it is not good to seek revenge. They could seek revenge back and make things worse.
Nah, I didn't take any thing from him, so he can't do anything to me.
He could resent you for giving him more work. It's important to maintain good relationships with people we work with.