What is one of the best or most worthwhile investments you have ever made — of money, time, or energy?

My country is a country of teachers. It is therefore a country of peace. We discuss our successes and failures in complete freedom. Because our country is a country of teachers, we closed the army camps, and our children go with books under their arms, not with rifles on their shoulders. We believe in dialogue, in agreement, in reaching a consensus. We reject violence. Because my country is a country of teachers, we believe in convincing our opponents, not defeating them. We prefer raising the fallen to crushing them, because we believe that no one possesses the absolute truth.

The friends with whom I sat on graduation day have been my friends for life. They are my children’s godparents, the people to whom I’ve been able to turn in times of trouble, people who have been kind enough not to sue me when I took their names for Death Eaters.

Remember, if you sit at your desk for 15 or 20 years, every day, not ­counting weekends, it changes you. It just does. It may not improve your temper, but it fixes something else. It makes you more free.

In the last 24 years that I have played for India I have made new friends, and before that I have had friends from my childhood. They have all had a terrific contribution. As and when I have called them to come and bowl to me at the nets, they have left their work aside to come and help me. Be it joining me on holidays and having discussions with me on cricket, or how I was a little stressed and wanting to find a solution so I can perform better. All those moments my friends were with me. Even for when I was injured, I would wake up in the morning because I couldn't sleep and thought that my career was over because of injuries, that is when my friends have woken up at 3 o'clock in the morning to drive with me and make me believe that my career was not over. Life would be incomplete without all those friends.

I think chess — actually, a number of things that I learned when I was young — it wasn't so much the chess itself; it was the skills that you were training while you were playing chess. So problem-solving, imagination, creative thinking, strategic thinking, all of these things — if you play chess to a high level, what you're really honing is those meta-skills. And I realized from quite young, that's one of the reasons I liked chess was this is a great practice for me to get good — sort of like a mental gym, if you like — to get really good at those other skills, which you could then translate to all sorts of other subjects like science or business.

Of all the gifts that tennis has given me over the years, the greatest, without a doubt, has been the people I've met along the way: my friends, my competitors, and most of all the fans who give the sport its life.