I hated running until I was about 40. I was good at it in the Army--I could consistently do a sub-6 mile/sub-12 2-mile, and at 4-6 I was sub 7, but I still hated it. It wasn't until years later, after I wrecked my shoulder in a bike wreck and couldn't ride, so I had to run for exercise that I learned to appreciate it. The thing about running is it's inefficient (especially compared to cycling). There is no way to make it easier, and running faster is harder. Full stop. But I learned to appreciate the zen-ish nature of it, and the inefficiency. I've maybe only twice (if that) had a "runner's high,"* but I've learned to appreciate finishing a run and knowing that I just did something for myself.
Rather than a runner's high, I think of it as "beautiful suffering." Same thing when climbing a monstrous hill on a bike.
*In the Army, I finished a brutal 12-mile run--it was awful--but grabbed the literal best glass of orange juice I had ever had when I finished. I was the second guy finished out of our battalion, and after my best buddy, a Ranger, kept me going through miles 7-8, at mile 11 he told me to go on without him--and that guy was (is) bleeping tough (he kept running and finished, just not at the pace we were using to try to catch the first guy). The juice was out of a carton in the fridge in my office--generic carton orange juice--but man was it just exactly what I needed in that moment. (Body wanted energy, and sugary fruit juice sent signals to my brain that were exactly right.)
