What is something petty you do to get back at someone?

I can spot knockoff luxury goods like a police dog. My mom taught me how growing up and I think it's a valuable skill. If someone has a knockoff I normally don't say anything but if this person is going around being rude and acting like their shit doesn't stink then I will call them out in front of everyone thus embarrassing them.

I pulled this stunt at my brother's high noon tea party where him and his fiance opened engagement presents. Some lady who was just the mother of a friend of the bride was acting all snobby and rude to me and I called her out in front of everyone. That's what you get for being mean to me and others. Uh huh your Burberry bag was a fake. It was a good fake but still a fake. I shut her down fast.