I’m a reasonably mild-mannered, agreeable person who tends to get along with everyone.

But if you disrespect me in any way—watch out! I undergo a terrifying transformation into a mild-mannered, agreeable person who makes a gesture of disapproval so subtle you’re extremely unlikely to notice. So I’m warning you: do not cross me, unless you’re confident you can handle potentially soul-destroying but likely imperceptible vengeance.

Babysitter, you will rue the day you decided to answer honestly when I asked how my kids behaved while I was gone. As I count out your pay and unaccountably add a giant tip I can’t afford, I will raise an eyebrow the tiniest fraction of a millimeter. And the next time my husband and I summon the energy to pretend to be normal people who go on dates instead of the dried-out husks of our pre-children selves we actually are, I will briefly consider seeking out a new, tactful babysitter. Then I’ll call you, tell you how much my kids love you, and beg you to babysit again. As I hang up the phone, thanking you profusely, beware: I may roll my eyes. Good luck living with the terrible crushing burden of my invisible scorn.

Colleague, I noticed you looked at me again when you asked if anyone would volunteer to take notes. But stop to think: How are you going to feel later, when you read the meeting minutes? You’ll be devastated to see I only included six smiley faces when there were clearly seven smiley face opportunities.

Students, don’t you hand in that paper late again. If you do, I swear to god, I will fully intend to take two out of a hundred points off your essay grade, but then I’ll probably forget when the time comes. And then a year later, when you ask for a letter of recommendation, I will hesitate a split second before responding, “I’d be glad to! When do you need it by?” That hesitation, should you notice it, which is unlikely since it will occur while I’m alone in my office reading the email in which you misspelled my name, will haunt your dreams.

Dude in the giant truck behind me at the stoplight, surely you noticed me accelerate quickly. But did you see how I shattered your psyche by pursing my lips slightly because you beeped at me the second the light turned green? That’s right, I’m tough and mean too. See you in hell.

I’m a hot-tempered, dagger-eyed, razor-tongued wild woman. I’m a loose cannon. At any moment, I’m likely to say something like, “So sorry!” or “Thanks! Have a great day!” in a tone almost indistinguishable from my regular voice—yet faintly too cheerful to be sincere. Impatient person behind me at self-checkout? Boss who implies that if I need to leave early to pick up my sick kid it means I don’t care about my job? Guy who often mixes me up with another middle-aged lady in our social circle because women of a certain age are completely interchangeable to you? You may never recover.

Bestie, you’ve been dead to me for decades. And I’ll prove it by sending you a handwritten card on your birthday each year for the rest of your life, and every time we see each other, I’ll say, “We should do this more often!” But am I being sincere? Well, yes. But when you text me, “Love you!” I’ll torture you a while before I write back. Those eight long seconds will give you plenty of time to wallow in profound regret about the seventh-grade spring formal when you danced to Boyz II Men’s “End of the Road” with Mikey Scanlon even though you knew I had a crush on him. Love you too!

So don’t dare mess with me. Every minor perceived slight will be visited back upon you a hundredfold. Or at least a hundredthfold: I will say and do almost exactly what I always say and do, and we will have an uneventful exchange that you will never think of again. And if you imagine you can handle the pain so you decide to fuck with me anyway? No worries! Have a wonderful day!