Mark Cuban: Why they fail

When Mark Cuban returns for the eighth season of "Shark Tank" on Friday night, he will be looking for new businesses and products in which to invest his billions of dollars. But he doesn't go after every deal he's pitched -- even if he thinks it's a good idea. He says he knows what he's good at, and he sticks to that. "The idea is the easy part," says Cuban, who joined ABC's "Shark Tank" in its second season as a guest "Shark" and became a series regular in Season 3. "We've all had ideas; everybody you know has had an idea. They get all excited about it. They think that nobody's ever done it because it's not on Google. Then rather than saying, 'Okay, let me see if I can sell any,' they think, 'Okay, can I raise money?'"