Both Tesla CEO Elon Musk and Amazon founder Jeff Bezos built empires by learning to think differently than the average person. It’s apparent they’re more intelligent than the average person, but they also possess an obsession with making their products better.

Constant improvement necessitates the ability to think critically. Critical thinking is the process of deep and careful thought about a subject or idea. This includes being able to analyze and weigh facts effectively, reason carefully, and make insightful connections. However, to Musk and Bezos, critical thinking isn’t just about being deeply analytical, it’s about actually being critical, looking for something wrong, something that can be improved.

“I’m always looking for what’s wrong,” Musk revealed in one interview. “In order to make [Teslas] better…I have to think very critically. So, when I see the car, I see all the things that I think need to be fixed to make it better.”

Bezos expressed a similar thought years ago when speaking to Jason Fried, CEO of Basecamp. “[Bezos] observed that the smartest people are constantly revising their understanding, reconsidering a problem they thought they’d already solved,” Fried says. “They’re open to new points of view, new information, new ideas, contradictions, and challenges to their own way of thinking.”

Critical thinking requires patience, a degree of emotional intelligence, and the ability to understand your emotions and keep them in balance.