It just seemed like a really good idea.
I believed all the data about the health benefits, I closely read and accepted Lieberman's endurance hunter hypothesis, I bought into the notions of accessibility and I noticed that it seemed an activity that I could continue into old age.
I like things that are individually difficult, and I especially like things that show slow, incremental improvement. So, I just put my head down and do the thing, and I improve at the thing? With said thing providing myriad benefits, the science of which I accept?
Okay then, let's do the thing.
Overall, the greatest benefit for me is anxiety control. When I first began, I was injured so much and read so much about it I switched careers from journalist to physical therapist. Over many years (and a great deal of learning) I found that running conservatively today, and also tomorrow, is far better than busting a gut today and spending three weeks without my most powerful anti-anxiety medication.
It's for this reason I never track my runs, even for time and never take any notice of weekly mileage. I run very conservatively, as often as I can and if I feel a niggle I take the day off. And that's it.