First, a personal experience: why did I run marathons?
From 0 to 10km: About six years ago, I decided to get fit. I decided that my first steps would be to run 30 minutes per day and to register for a 10km race (2 weeks after the actual day). The next day, after putting my sport shoes, I went out and started running. After about 30 seconds, I started to be breathless and my thighs started to hurt me so bad. I had to stop running after a minute… The next day, I decided to run 2 minutes per day instead. I did it. Two weeks later, I was running the 10km race. It was tough but I made it and something awesome happened at the arrival. Right after crossing the finish line, I stopped running and I started to feel so, so good. The (subjective) feeling was like a releasing of sweet chocolate throughout my whole body… Such a great memory. I then started to run 10km 2 and eventually 3 times a week.
From 10km to 42.125km: After a while, I was completely used to 10km. Running around 50min was not challenging anymore (at a certain pace) and I definitely saw an improvement in my overall physical and mental health. At this moment of my life, I thought that running a marathon was far out of my abilities. One event really changed my way of thinking: During my sophomore year in college, I was considering studying abroad. I was thinking of Europe because I thought the USA were exclusive for the elite (crazy rich and crazy smart). One day, I saw an advertising about getting a grant to be an exchange student in America. I decided to give it a try. I will always remember the moment I heard that I got selected. Again, the sweet chocolate was flowing through my veins… Such a great memory. But more than making me happy, more than improving my self confidence, more than giving me an awesome opportunity: this event broadened my horizons. Few days after, I was registering for my first marathon and preparing my first training plan.
More concretely, 19 reasons to run a marathon:
#2 Improve self discipline (the training is actually a huge time commitment)
#3 Get a “Finisher” tee shirt
#4 Improve mental resilience
#5 Improve self confidence
#6 Be more resistant
#7 Get fit (as hell)
#8 Get a wonderful memory,
#9 You can run for charity
#10 It is actually fun
#11 For the challenge
#12 After you did it: it is forever in your done-list
#13 Because you can (a lot of people cannot)
#14 To feel like a bad-ass
#15 To learn about nutrition-muscles-cardio
#16 To laugh out loud when watching this
But my top-3 reasons are:
#17 It is actually a veritable voyage of discovery
#18 It makes you become a better version of yourself
#19 And last but not least: because it makes sweet chocolate run through the veins 😀
Originally answered by me: Quora link