Family. Friends. Sleep. Time to play.

For many people, these are the fundamental joys of life. But if you dream of being a entrepreneur, get ready to sacrifice them all.

That's according to Marcus Lemonis, a self-made millionaire and the star of CNBC's "The Partner."

"When people are worried they will burn out, about their work life balance, about quality of life, I am like, 'Okay, then go work somewhere and have a 9-to-5,'" says Lemonis, who was speaking at the SXSW Festivals and Conferences in Austin, Texas, on Saturday.

The idea of launching a start-up that grows to be worth billions of dollars in a few years, like Snap or Uber, is alluring, but Lemonis says most people don't understand what's really involved in getting a business off the ground.