How Assumptions Start Most Fights

Decades ago, I was the teaching assistant for a one week intensive course. Nine to five, every day. A small masters level class, about twenty people.

I still remember this one student. She was middle-aged, a little dishevelled, and always nodding off.

And in such a small class, when someone falls asleep, everyone sees it.

Day after day, I watched her eyes close. And day after day, my story about her grew. She’s being rude. She doesn’t respect the professor or her peers. Why did she even sign up?

On the last day, during the break, she came up to me. She asked if she could get a copy of the notes.

In my head, I judgedly thought, “Of course you do. You slept through half of it.”

Then she explained. She’d had a mastectomy two weeks ago. The painkillers made her so drowsy she could barely keep her eyes open. But this was the last class she had to take to graduate.

And she made herself a promise that she’d complete this course. So she did. She came to class. Every single day.

And I felt like the worst person in the world.

But she taught me a lesson that I still carry with me today. Assumptions hurt relationships.

Here’s why we make assumptions.

Our brain hates a gap. When it doesn’t have the full story, it makes one up. And it doesn’t pick a random story. It picks the one that matches what you already believe.

That’s called confirmation bias. It’s our brain’s habit of looking for information that proves what we already believe, while ignoring anything that doesn’t fit.

My brain said she was lazy. So I looked for cues to confirm that assumption.

And this is something we all do. Nowhere does it do more damage than in our closest relationships.

Your teenager comes home after curfew. Your brain says, “They’re ignoring my rules.” The truth? The bus never came.

Your partner walks in without the milk. Your brain says, “They’re always forgetful. I can’t count on them.”

The truth? They were running late at work because their boss needed something. They rushed home by six to take care of the kids because you had somewhere to be, and they didn’t want to make you late. They skipped the milk to get to you.

Notice what happened. In both stories, your brain filled in the gap and turned assumptions into proof of a problem.

That’s the danger. Most fights don’t start with what happened. They start with the story we made up about what happened. And most of the time, we’re wrong.

So how do you outsmart a bias that runs on autopilot? Here are three ways to start.

1. Say the magic words: “The story I’m telling myself is…” Before you react, say this out loud or in your head. “The story I’m telling myself is that you don’t care.” That one sentence separates fact from fiction. It reminds your brain that a story is not the truth.

2. Look for the evidence you’re skipping. Confirmation bias only collects proof that fits. So ask yourself, “What’s one thing that doesn’t fit my story?” Your partner remembered your appointment last week. Your kid texted in the past to check in. One piece of missing evidence can crack a false story wide open.

3. Get curious before you get furious. Swap the accusation for a question. Instead of “You forgot the milk!” try “Hey, what happened with the milk?” Almost the same words. Completely different outcome.

Here’s the truth. If you keep having the same fight about different things, the problem isn’t the milk. Or the curfew. Or the dishes. It’s the stories running underneath. And most of those stories are not true.

So this week, try one small thing. The next time your brain hands you a story about someone you love, hold it loosely.

Ask one question before you believe it. You might find out the bus never came. You might find out they skipped the milk to get home to you. And you might just save yourselves a fight that never needed to happen.

I still think about that woman in my class. Not because of what my brain got wrong, but because of the lesson she taught me. That everyone we meet is carrying a story we can’t see. And it’s our responsibility to stay open and curious. When we do, we make space for compassion, kindness, and connection.

P.S. Stay curious. The kindest thing you can do for someone you love is ask for the real story before you believe the one in your head.