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.

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 started to be the brand, more and more. Seven days a week, 24 hours a day, I wear T-Mobile gear. I'm a bright beacon of magenta. My clothing's gotten more elaborate because a lot of people want me to wear their clothes! And then when I go to a call center, I give away my T-Mobile clothes, and walk out to my car with my socks on.

I think this job at T-Mobile has more than anything else helped me really see and understand how to set a strategy, communicate like crazy, and then passionately lead from the front of it.

My interaction with my followers on social media has become a phenomenon, and that's hardcore work every day! I have carpal tunnel from typing on my device.

Deutsche Telekom was a brand that people still loved, the nerds loved it, and it was still there, it was still visible. The advertiser was OK. But it was a mess. It was in my mind, though, intuitively obvious what to do. I had some advisers and friends, and we looked at it and said all you have to do is get the iPhone, buy some spectrum, consolidate the industry, reinvigorate the brand, and take this company public.