I tell employee of T-Mobile, "Listen, if some of this doesn't make sense to you, what should make sense is the reason I'm telling you - I respect you as an owner and as a partner and I'm going to tell you this all the time. Feel free to tune out."

If you go back in my career, you'll find I've always been a lead-from-the-front people-manager guy. I've always been outspoken. I've always attempted to break the mold. My advice to myself, then, would be to go all in on it. The world doesn't need another cookie-cutter business-school leader. The world needs somebody to stick out and be loud and proud.

When I finished my last job, at Global Crossing, it was the first time in God knows how many years that I wasn't in a job. It was probably 32 years or so, and there I was, it was like pow!

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.

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.

Strangely, from a life-change standpoint, I sold the company I was running and got divorced in the same month. And so there I was, at home, and I'm not the CEO. I took a few months thinking about what I wanted to do. When the first call came in about running a company owned by Deutsche Telekom, I thought it was laughable and really not something I'd do. I took the meeting mainly because the headhunter I knew. At first I thought I was just helping her fill out the roster, but then I dug into it.

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.