Facebook CEO Mark Zuckerberg took a bit of gentle ribbing during a Q&A session that was live streamed earlier this month.

One person asked a question that evidently has been on the minds of quite a few people: Why does he seem to wear the same gray T-shirt every day?

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Zuckerberg took the question in stride, even tossing the attention to COO Sheryl Sandberg, who acknowledged that her boss does indeed have more than one of his signature shirts. But deciding on clothing every day, Zuckerberg said, is just not something he wants to waste energy on.

"I really want to clear my life to make it so that I have to make as few decisions as possible about anything except how to best serve this community," he said.

Zuckerberg is not alone in this idea. Some of the most successful people, past and present, have viewed fashion as a frivolity. Others, like Australian TV host Karl Stefanovic, have used it to make a point about men facing less judgment about their wardrobe choices. Here's a few of the most famous examples.

Steve Jobs

Signature outfit: black mock turtleneck, blue jeans, New Balance sneakers

Image: Paul Sakuma/Associated Press

The signature look of the tech pioneer almost extended to Apple's staff. Jobs said he once attempted to design something of a uniform for employees, but it was roundly rejected.

Barack Obama

Signature outfit: blue or grey suit

Image: Charles Dharapak/Associated Press

The president made waves earlier this year when he hosted a press conference while wearing a tan suit. Obama is almost always seen in grey or blue suits, something he says helps pare down decisions. "I don't want to make decisions about what I’m eating or wearing. Because I have too many other decisions to make."

Albert Einstein

Signature outfit: copies of the same suit

OK, so scholars who studied Einstein say this is mostly false. His second wife, Elsa, reportedly kept the genius in sharp suits. However, as he aged, he did show a predilection toward cotton sweatshirts and sandals.

Dean Kamen

Signature outfit: denim shirts, denim jeans, work boots

Image: Suzanne Plunkett/Associated Press

The inventor of the Segway is known to be a bit eccentric. Kamen is still working on futuristic projects, most notably trying to perfect the Stirling engine.

Karl Lagerfeld

Signature outfit: black suit, white shirt, sunglasses, gloves

Image: Jerome Delay/Associated Press

Just because you're the creative director of Chanel, doesn't mean you have to keep up with the latest fashions. Lagerfeld might change it up a bit more than the other on this list, but his basics always seem to be in place.

Christopher Nolan

Image: Charles Sykes/Associated Press

Signature outfit: "a dark, narrow-lapeled jacket over a blue dress shirt with a lightly fraying collar, plus durable black trousers over scuffed, sensible shoes"

That's how the New York Times Magazine described Nolan's typical attire. Nolan "long ago decided it was a waste of energy to choose anew what to wear each day," according to the recent profile of the Interstellar director.

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