To be petty is to be human, and while living in a state of pettiness isn't mentally healthy or sustainable, it can feel good to let it out on occasion.
Sometimes, all you can do is let someone know just how low you can go as a warning, so they know not to cross you in the future. At the very least, so they know what they're getting into if they press you on the wrong day.
Naturally, the internet is a sea of receipts, so there are countless posts documenting and recounting petty exchanges, here are a few of the golden ones.