Being grateful is the key to happiness, says entrepreneur, philanthropist and New York Times Best-Selling Author Tony Robbins in an interview with TheStreet.

In his latest book, Unshakeable, Robbins says it's nearly impossible to be angry or fearful when you're grateful. And making more money is not the answer, nor is it the path to gratitude. Controlling your mind and focusing on what's important is the key to happiness, says Robbins.

You can train your brain to be grateful, he says. 

"There are two things that mess up your relationships, it's anger and fear," explains Robbins. Robbins points to Salesforce (CRM) - Get Report CEO Marc Benioff as being a total giver, which has set him up for success in business. 

Check out more of TheStreet's talk with Tony Robbins: