Uber, Twitter, Stripe, Instagram: Chris Sacca has made some pretty good bets on startups. And in the course of making those bets, the sometime Shark Tank star has developed some reliable rules of thumb for identifying the entrepreneurs worth getting behind.

"Having done this for a lot of years now and having a lot of data points, I can just tell," he said in an on-stage interview at the Collision Conference in New Orleans Thursday. "I can smell it on them, whether they're going to go the distance or not."

Confidence, as you might expect, looms large, but it's "a confidence without needing to sell," Sacca told CNN's Laurie Segall. "Our best founders, whether it's Travis [Kalanick of Uber], Evan [Williams of Twitter and Medium], or Kevin Systrom [of Instagram], they just believe in the inevitability of their success." When things don't go as planned, he said, "they don't wallow, they just know it's going to work out."

Kalanick's vision for Uber was already unstoppably huge even when its "fleet" consisted of three cars in San Francisco, Sacca said. "In the earliest days, when he was pulling eight-hour days in our hot tub up in Truckee, we were talking about international expansion. We were talking about moving food and packages around."

Likewise, Systrom was projecting 50 million users for Instagram before it had any at all. "He said it so calmly, it was magnetic. It was alluring," Sacca said. "I said, 'I can't not be involved in this guy's company.'" 

But that's not all Sacca looks for in a great founder. He also wants a degree of dysfunction. People who are completely normal may make wonderful employees but they shouldn't be entrepreneurs, he said. 

"This is a very special, different journey that's not available to everybody," he said. "You have to be a little obsessive. You probably have some personal issues that make you different. You may have trouble relating to other human beings. You don't accept failure very well. Maybe you're a little manic-depressive.

"If none of those things sound familiar, you should think about doing something else."