Part of my role at T-Mobile is the ability to just be myself, because I'm 58 years old and I've done very well, and I don't need to fight my way up the hierarchy with my suit and hair anymore.

When I go to T-Mobile retail stores, I jokingly tell the employees that everybody between me and them is the enemy. In effect, what I mean is that in my paramilitary hierarchy, if I can hear them and they can hear me, everything will be fine. All we need to do is make sure the entire company understands that it's their job to pass information between us. And so far so good.

I've given my email address to all 3,000 T-Mobile stores. Serious customer escalations come directly to me. Customers get a kick out of me responding to them, and the employees do, too.

It's kind of fun at my age to go back and talk to business-school people. I tell them, "I can summarize everything you need to know to lead a major corporation. Are you prepared to write this down?" And then they get all ready. I tell them I can summarize how I succeed as a leader: Listen to your employees, listen to your customers, shut the f - - up, and do what they tell you.

When I used to live in Asia, they used to say, "If you're going to sing karaoke, you want to go after the worst singer." And I'd be coming in Deutsche Telekom after the worst singer.

I'm very careful, especially with the company, to not spend too much time playing the success reel because I really do believe that everything that's been accomplished can be parlayed in an equal amount going forward.

I visit T-Mobile call centers. We've got about 18 major call centers in the US, and before I was CEO, I heard that no CEO had gone to physically visit them. I go in, they meet me outside, we take selfies as I stand like a piece of furniture, I tell them about how things are going - but most importantly, I say thank you and help them see that their behavior and their work has driven the culture of the company that's changed the industry and the whole world. It's a bit of a love affair.