Mark Cuban didn't always consider himself a nice person.
When Cuban was in his 30s, running the tech company that would eventually make him a billionaire, he was laser-focused on productivity and results, he told the "Bio Eats World'' life science podcast on Tuesday.
These days, he regrets it. "I wish somebody would have told me to be nicer," said Cuban, 64, when asked what advice he'd give his younger self. "Because I was always go, go, go ... Ready, fire, aim. Let's go. Let's go faster, faster."
Cuban and his business partner Todd Wagner joined AudioNet, an audio streaming company, as co-founders in 1995 — alongside its original founder, Chris Jaeb. The company was later renamed Broadcast.com, and acquired by Yahoo for $5.7 billion in stock in 1999, making Cuban rich.
At first, Cuban's hustle-forward outlook tanked the company's morale and performance, he said: "Sometimes it took my partner Todd telling me, 'Look, you're scaring some people, [and] they're typically going to [quit] and you can't get mad.'"
The business may not have grown so much — and Cuban might not be a billionaire — if he hadn't learned the "underrated" skill of being nice, he told Vanity Fair in 2018.
"I went through my own metamorphosis, if you will. Early on in my career," he said. "I wouldn't have wanted to do business with me when I was in my 20s [and 30s]."
"So I had to change, and I did, and it really paid off," he added.
Kindness is a valuable leadership trait, according to a 2020 Gallup survey which found that workers have "four universal needs" when it comes to their bosses: trust, compassion, stability and hope.
Those traits are correlated with better business performance, Gartner director of research Caitlin Duffy told CNBC Make It last year: Employees become more engaged in their work, leading to higher productivity, lower staff turnover and overall monetary gain.
"It not only affects employees themselves. It has a downstream impact on the business," Duffy said.
The proof extends beyond Cuban. For example, Lyft co-founders John Zimmer and Logan Green built their company using a "nice guy strategy," Zimmer told the Financial Times in 2017.
"For a while, there was this idea that we are treating people well, and we are going to get beaten by a competitor that is more aggressive," Zimmer said. "There was a misunderstanding about those values [not being] tied to building a great business, which they are."
At the time, Lyft was reportedly valued at $7.5 billion. It had a market cap of $3.59 billion in March, when Zimmer and Green announced they'd step back from day-to-day management duties.
Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank," which features Mark Cuban as a panelist.
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