This Founder Says to Succeed You Need to Question Everything Zocdoc founder and CEO Oliver Kharraz values learning about perspectives other than his own and questions assumptions you believe to be true.

Editor's Note: Entrepreneur's "20 Questions" series features both established and up-and-coming entrepreneurs and asks them a number of questions about what makes them tick, their everyday success strategies and advice for aspiring founders.

When you're sick, the last thing you want to deal with is stressful logistics like finding someone you can trust, getting into see a specialist and seeing if the physician takes your insurance. Oliver Kharraz feels your pain.

After studying and practicing medicine for years and coming from a 300-year-old family tradition of careers in medicine, he believed that he could make a difference in the lives of patients from a boardroom, rather than an exam room.

In 2007, the German-born entrepreneur launched Zocdoc, an online platform that lets patients make appointments with doctors with the click of their mouse, to make it easier for people to get help when they aren't feeling so hot. It also lets users read patient reviews of the physician, sends reminders about annual checkups and makes it easy to fill out paperwork online ahead of time.

"The problem is that I was helping people one at a time when I was working as a doctor, which is both satisfying but also limiting. So I wanted to help patients on a larger scale, which is why I started Zocdoc," Kharraz says. He explained that he founded the New York City-based company with the goal of using technology to lower the inherent tension around health-care experiences

Nine years after its launch, Zocdoc's services are available all over the the country, and 60 percent of the U.S. population can access a provider on its platform, given the company's geographic footprint, according to the company. More than 6 million patients use the service each month, and they are able to book more than 1,800 different kinds of procedures across more than 50 medical specialties. The typical Zocdoc user gets into see a physician within 24 hours, which is 18 times faster than the national average, the company claims.

We caught up Kharraz and asked him 20 questions to figure out what makes him tick:

1. How do you start your day?
I get up an hour early in the morning before my wife or children wake up. It's a great time to read and get exposed to new ideas outside the scope of what I do day to day.

2. How do you end your day?
I try to end each day with my family, either physically with them or on FaceTime. It keeps me grounded.

3. What's a book that changed your mind and why?
I wouldn't even say it changed my mind but created my mind. Critique of the German Intelligentsia by Hugo Ball. It's a little bit out there. This book worked out the complete randomness of the outcome of our thought processes. Once you understand that a lot of the things you believe to be true are just assumptions -- that others didn't share before a certain time and people in other countries don't share -- you really start questioning your own thought processes.

For me, this has been a pivotal book that made me think deliberately. It's a big ingredient to how we work at Zocdoc. There are so many givens in healthcare that people just believe have to be true but questioning them can be very effective to start a contrarian conversation.

4. What's a book you always recommend and why?
Thinking Fast and Slow by Daniel Kahneman. It's a great book that explains the physiology of our thought processes. I believe that once you are more aware of how you think, you will have better outcomes.

5. What's a strategy to keep focused?
I had the benefit of studying at a Jesuit monastery. We studied complicated texts and immersed ourselves, pushing our attention spans to the very limit. It's like meditation in that you learned to direct your thoughts. It's an active skill, like working out.

Pick something that you want to think about, and only think about that. Don't let anything else enter your thoughts. Try for five minutes in the beginning -- and know that just like a marathon where you start with just a half mile to begin with, in the end you'll be able to do it for hours once you train for it.

6. When you were a kid what did you want to be when you grew up?
A doctor. My father was a doctor, his father, and his father before that. It was really passed down in my family. In a lot of ways the underlying value for this was that I've always been taught that talent breeds responsibility, and so being a doctor was a very direct way to live up to that responsibility.

7. What did you learn from the worst boss you ever had?
I learned to only make promises that I can keep. I remember how upset I was when promises were made to me that were not kept, and I promised myself that I wouldn't do that.

8. Who has influenced you most when it comes to how you approach your work?
My mother. She taught me about discipline, and if you say you're going to do something, you have to do it. She taught me about what it means to live up to my worth.

9. What's a trip that changed you?
The single most pivotal trip in my life was being a foreign exchange student in the U.S. when I was 15. The stark difference coming from Germany to the States is this incredibly optimism, can-do attitude, the vision that life is getting better from generation to generation and not a downhill race. It's a version of the American Dream that makes you feel you are proud to be part of a community that can tackle so much and is not afraid.

10. What inspires you?
The fact that change is possible. If we look back at what's been achieved in the face of incredible odds, it's amazing. The fact that our forefathers were able to get rid of a well-entrenched dictatorship that had an entire continent for a few thousand years and then establish something new on a concept of mutual checks and balances and understanding of human nature. It set an overwhelming precedent. Compared to that, whatever problems I face seem extremely solvable.

11. What was your first business idea and what did you do with it?
The first business was right out of high school, pre-internet, email companies. Back when email took five days to get from Munich to Los Angeles, I was running one of those services in the early 90s. I realized that the internet was coming and that I had two choices: to either double down on the company and dropout of college or sell the company and finish college. I opted for the latter, a great decision. It protected me from too much money early on in life, and shortly thereafter, the internet bubble inflated. It was a great experience.

12. What was an early job that taught you something important or useful?
I worked as a nurse's assistant to understand what it would mean to execute a doctor's orders -- I didn't want to ask someone to do something that I hadn't done myself. Some of these patients were very sick and helpless. It was great lesson in humility and to be thoughtful about what you ask of people who you have a responsibility towards.

13. What's the best advice you ever took?
Something that my dad taught me early on: talk less, listen more. When I took the CEO job at Zocdoc, I went on a listening tour for the first 100 days to find out what are the priorities. I think that has been a recipe that has worked well for me.

14. What's the worst piece of advice you ever got?
When we launched Zocdoc, there was a lot of investors that told us to go national right away. We had launched only in Manhattan, and we stayed in Manhattan for three or four years, which is forever in internet time. To actually learn how the business works at the smallest possible scale before we expanded as to the complexity of the business and ignoring the advice to go broader and staying hyperfocused early on was was crucial to our success.

15. What's a productivity tip you swear by?
To work uninterrupted. Block time on your calender, focus on doing one thing at a time and do it deliberately. And then move onto the next. And as a neurologist married to a medicine sleep doctor, I'd say get a good night sleep.

16. Is there an app or tool you use in a surprising way to get things done or stay on track?
This may date me, but I still use pen and paper for priority projects and even developing new ideas. You have the choice to draw things or write things and sometimes one is more appropriate than the other. You can mix and match them in a way you can't do on the computer yet.

17. What does work-life balance mean to you?
My way of dealing with that is to protect my weekends as much as I can and get most of my work done during the week.

18. How do you prevent burnout?
It might sound a bit boastful, but I don't think that I'm very prone to that. I'll give you an anecdote that might shed some light on that. My dad, when he was 68, he retired for a couple of months and said I'll go back to work for a day a week. And he expanded to two days. He's 79 now and he works six days a week. I just think that it's in my DNA. I'm probably more of a workaholic than someone who wants to take a rest.

19. When you're faced with a creativity block, what's your strategy to get innovating?
I expose myself to new ideas through reading and talking to people -- friends who are active in completely different spheres. Many friends -- both in healthcare and who are artists, writers and very pragmatic types -- all have a unique way of thinking about things.

There's also a lot we can learn from people who are no longer around. I read about history, religion, economics. I'm a little bit of a science-fiction geek. I like to look back at what people dreamt about how the future would be. I get inspired the most by things that didn't go as predicted.

20. What are you learning now?
One of the most humbling experiences is probably having kids and learning to be a father. The difficult balance is to learn how to guide while also giving autonomy at the same time, which is also a trait I'm learning to do right now as a CEO.