“Shark Tank” judge and Dallas Mavericks owner Mark Cuban appreciates efficiency. That’s part of the reason you’ll rarely find him in a boardroom.”I hate meetings,” he said on an 2019 episode of GQ’s “Actually Me.” “Nobody likes meetings except the people who bring the doughnuts and the people who love to talk about their kids.”Oftentimes, they’re a productivity killer, Cuban says. Half the time is wasted talking about “all this nonsense that has nothing to do with getting the job done,” he added.Rather than taking meetings, Cuban prefers to do most of his business over email to save time. Plus, it provides a paper trail. “I want to do everything via email because that allows me to go back and look something up,” he said. “I can go back and search it five years, 10 years, 20 years [from now]. I’ve got emails that are 25 years old.”The self-made billionaire has been consistent with his stance on meetings. When asked about his “secret life hack” in a 2016 Thrive Global Q&A, he said: “No meetings or phone calls unless I’m picking up a check. Everything is email. … Saves me hours and hours every day.”He’s not the only billionaire who avoids meetings. Tesla and SpaceX CEO Elon Musk isn’t a fan and has said that meetings are what happens when people aren’t working.”Excessive meetings are the blight of big companies and almost always get worse over time,” Musk said in a 2018 letter to Tesla employees. “Please get [out] of all large meetings, unless you’re certain they are providing value to the whole audience, in which case keep them very short.”And don’t be afraid to leave one if you’re not contributing, he said: “Walk out of a meeting or drop off a call as soon as it is obvious you aren’t adding value. It is not rude to leave, it is rude to make someone stay and waste their time.”Excessive meetings are the blight of big companies and almost always get worse over time.Elon MuskTesla and SpaceX CEOResearch is in Cuban and Musk’s corner: Researchers from Harvard Business School and Boston University surveyed 182 senior managers across industries and found that the majority (71%) think meetings are unproductive and inefficient. And 65% said they keep them from finishing their own work.That said, it may be impossible to completely eliminate meetings from your schedule, the research team notes: “Just think how many times you’ve tried to reduce the number of meetings on your calendar — probably with limited success.”If that’s the case for you, it’s important to get the most out of them, which may mean changing your process. Start by surveying your team to figure out exactly what’s working and what’s not working in meetings, the research team suggests.Then, “agree on a collective, personally relevant goal. We have found that personally benefiting from the group’s initiative is a great motivator. For example, you might designate a certain amount of time each week for people to focus on independent work — whether in the office or at home.”Ultimately, “Meetings do not have to be a trap,” the report concludes. “They can be a conduit for change.”Disclosure: CNBC owns the exclusive off-network cable rights to “Shark Tank.”Don’t miss: Mark Cuban recalls the moment he told his dad he made $100,000 for the first timeLike this story? Subscribe to CNBC Make It on YouTube!