After Sunday’s episode of reality TV drama 90 Day Fiancé, people were left with an important question: is it ever OK to correct someone’s grammar? The show follows long-distance couples in a pressure cooker: when the foreign lovers of American citizens move to the US, with just 90 days to decide whether to get married before their visas run out. Sunday’s episode saw couple Stephanie Matto and Erika Owens hash out what went wrong in their failed relationship, and some viewers suggested that a screenshot showing an exchange between them might sum their problems up. “I’m so sad about this,” Owens texts Matto, seen in a WhatsApp chat. Then she adds: “I feel so lead on.” “*Led,” responds Matto. Ouch. There are a select number of situations in which someone is allowed to correct someone else’s grammar: if you are a teacher; if you are paid to correct grammar or proofread work; or if you are a parent. Then it’s acceptable to say: “Actually, it’s you’re, not your.” In some cases, the question is blurrier. Perhaps you’re learning a new language, and you have either asked, or the other person assumes, that you’d appreciate not looking silly every time you get something wrong. If you are a waiter and your boss corrects your grammar because they’re worried about the impression you give off, or if you’re the nanny to someone’s children and the parents are worried you’ll impart incorrect wisdom … then it becomes a little more subjective. Some might say that if good grammar isn’t in the job description, it shouldn’t count; it could certainly end up feeling like an overreach of someone’s power if they continue to correct you. But if you correct someone’s grammar in the middle of an argument, even if you are in any of the above positions, you are most likely wrong. Sure, they may have meant fewer, rather than less. But it is both a power move and a way of detracting from what the person is saying, of putting them down instead of listening to the substance of their argument. Slate summed up exactly what’s wrong with this when it coined the term “language bully” in 2013. There’s nothing wrong with knowing more than others, writer Matthew Malady wrote, but “those who use their advanced knowledge to embarrass or humiliate others are the absolute worst”. If correcting someone else’s grammar is routine for you, consider this: are you genuinely trying to help, or are you just trying to gain the upper hand? Are you listening to what the other person is saying, or simply looking for an excuse to show them that they are wrong? And really, does it matter that they confused their and there, or could you let that one go this time?