The Gas Cap Rule: Why smart people miss obvious solutions

A broken lawnmower. A guy out of ideas. And a mechanic who solves it in less than 15 seconds — in an underrated moment from Sling Blade (1996) that’s basically a masterclass in clear thinking.

The mower won’t start. One of the guys from the shop — a regular employee, not someone you'd call slow — has already been fiddling with it. Filthy from head to toe, he’s been at it a while. By the time Karl is finally called over, the shop owner and the mower’s owner had nearly run out of small talk.

Then Karl, a simple man, walks over. Doesn’t touch a tool. Doesn’t ask a question. He unscrews the gas cap, looks inside, and says:

“Ain’t got no gas in it.”

That’s it. Problem solved. No theories. No monologue. Just the most obvious explanation checked first.

That’s the Gas Cap Rule.

Start with the simplest, most obvious explanation before diving into anything else. Not because it’s clever. Because it works. It saves time, money, and energy. It’s not about thinking less. It’s about thinking in order. You can build models later. But first, open the dadgum gas cap.

We love complexity. We love thinking we’re three moves ahead. So when something doesn’t work — in business, in relationships, in life — we rush to diagnose:

“Maybe it’s pricing psychology.”

“Maybe she's emotionally unavailable.”

“Maybe it’s brand saturation.”

Maybe. Or maybe it just ain’t got no gas in it.

• Sometimes your offer isn’t converting because nobody saw it.

• Sometimes she didn’t reply because she’s just not into you.

• Sometimes your strategy isn’t working because it’s the wrong strategy.

We skip the obvious all the time, because it feels too easy.

Smart people are the worst at this. The smarter we are, the more we’re trained to look ahead, build systems, find patterns. But sometimes, there’s nothing to decode. The tank is just empty.

There’s a reason this scene lands. It’s not just that Karl was right. It’s that everyone else missed it. The mechanic was just aimlessly yanking the cord, hoping to get the engine would to turn by sheer willpower. The shop owner didn’t have any ideas.

Karl wasn’t trying to diagnose anything. He was just looking at what was right in front of him.

That’s what makes the Gas Cap Rule so useful — and so rare. It asks one thing: What’s the simplest version of the truth?

At What’s Likely, the Gas Cap Rule isn’t a step. It’s where everything starts. Before we touch data or build scenarios, we ask: “What’s the most obvious reason this is happening?”

It’s far from the only thing we do, but it’s always the first. Because if the problem is simple and we miss it, nothing else matters. And if it’s not simple? We have the tools to go deeper. 

But we won’t recommend buying a new mower until we know if there's gas in the mower you already have.

Karl didn’t give a TED Talk. He didn’t explain his process. He just walked up, looked, and said what he saw.

That’s the Gas Cap Rule. Not analysis. Clarity.

Thanks to Karl. Thanks to that mower. And thanks to one perfect line:

“Ain’t got no gas in it.”

Jacob Brower is the founder and chief strategist of What’s Likely, a decision-support tool that forecasts the most probable path to success. He is also president of Archer's Bow Media & Marketing and ABM Strategies.