I was talking to one of my favorite INTJs, and he told me he has pet rats. I assumed two. Rats are social. Then he said ten. He has ten rats.
This is in San Francisco, which means he basically has a million-dollar rat room. He also has a boyfriend. They both have impressive jobs. They are, by any normal standard, high-functioning adults who live with ten rats.
When I asked why, he said, “They’re just pets. Like any other pet.”
But rats are smart. Their intelligence is comparable to dogs, pigs, even dolphins. If you have a smart animal as a pet, the point is usually connection. Time. Bonding. Interaction.
But these two guys work full-time. They are not spending their days teaching rats to run mazes one by one. So what exactly is happening?
What’s happening is an INTJ thing.
My friend is exceptional at his job. His work is all about building systems, finding inefficiencies, fixing them, and moving on. And this is what he did with rats.
Instead of asking, What kind of relationship do I want with this animal? he asked, How do I design the optimal system for rat wellbeing?
He built an entire environment. Materials to burrow. Structures to climb. Space calculated to meet ethical standards. No one could argue that the rats were poorly cared for. But that’s beside the point.
An INTJ can make anything efficient. But it’s much harder to choose the right recipient of that efficiency.
There’s a real aesthetic pleasure when an INTJ sees an efficient system. When something runs cleanly, logically, with no waste, it feels almost moral. For an INTJ efficiency starts to feel like meaning, which is how you end up with a beautifully optimized system that doesn’t actually matter.
We don’t need rats to be well cared for. We’re at war with rats. We kill tens of thousands of them a day in U.S. cities. If you wanted to meaningfully improve the world for rats, you could work on human-rat coexistence, like what’s being explored in Paris. You could tackle public health, infrastructure, urban design. But designing the perfect system to live with ten rats is efficiency without direction.
When I pushed back, my friend didn’t get defensive. He’s an INTJ, so he sent me research. Ethical standards for rats. Space requirements. Stimulation needs. There are even protocols for how long and how often rats need stomach tickles.
The research was fascinating. And he used it to do exactly what I should have expected: Not to rethink the mission but to add another layer of efficiency.
Here’s what INTJs are good at recognizing at work: bullshit. You don’t get pulled into pointless meetings. You don’t work on projects that don’t matter. You instinctively focus on what’s important to the company.
But you don’t apply that same filter to your personal life. It’s not just rats. I see INTJs build elaborate systems for their kids—educational plans, well-researched rules, perfectly balanced structure. And if you ask what they want for their kids, they'll say something like “an independent thinker”. But that's a quality, not a vision. Independent thinker doing what? Working toward what? It gets the kid to eighteen with no idea what comes next.
So when you feel the pull to optimize something outside of work, ask: what is this system actually for?
It’s fine if the answer is “efficiency feels good.” Just be honest that you’re choosing the aesthetic pleasure of optimization, not impact. But if you thought you were doing something meaningful, and the only actual goal is that the system runs cleanly, then you’re lying to yourself.