I was eighteen years old, a stubborn dreamer with something to prove to myself, and just like that it came to me:
I was going to run the Boston Marathon.
It was an insane impulse. I was only running about three miles a day, but I was convinced I could run 26.2 miles as easily as I could cover three. What's the big deal? You just keep going.
That's how you think when you're eighteen, with no real plans for the future and nothing to lose. You shoot for something crazy, just for the drama of it.
I told my parents I was going to Boston to run the marathon, and all they could do was stare at me. I might as well have told them I was going to pitch for the Yankees tomorrow night.
But bless their hearts, they didn't stop me from going.
My grandmother tried to stop me. She was dead set against it. Like most Italian-Americans of her generation, she didn't understand running. In her Brooklyn neighborhood, the only running she'd ever witnessed was the kind triggered by burglar alarms.
"Running," she warned me matter-of-factly, "makes you sterile."
That particular theory of hers had something to do with snug underwear, and the friction generated by all that legwork. A hell of a theory.
But I was determined to run the race, even at the risk of costing Grandma a great-grandchild or two.
As far as I was concerned, the stars were aligned in my favor. I'd gone to college in Boston for a little while, so I had friends I could crash with. I had the train fare to South Station.
And I thought -- repeat, THOUGHT -- I had the legs for the big race.
So I took the train to Boston, and on the morning of the race I hitchhiked to the starting line, catching a ride with a carload of born-again Christians.
They drove me right to the gym where all the runners gathered, wished me luck and said Jesus would be with me every step of the way.
Well, if He was, He riding on my back, making an impossible task even tougher.
One look around the gym told me I'd made a huge mistake. All these people were built like jackrabbits, with special running shoes on their feet.
Me? I wasn't fat, but I had twenty pounds on everybody. Plus, I was wearing basketball sneakers. Basketball sneakers! They had about as much support as bedroom slippers!
Worst of all, everybody else was wearing paper numbers on their chests. They'd qualified for this event, registered for it, planned way ahead.
I was just a dumb kid who'd thumbed a ride to the starting line of the world's most famous race. I did not belong there.
A tap on my shoulder -- this is it, I thought, they're throwing me out of the gym, out of the race, out of Boston!
But no -- it was another runner, smiling and friendly.
"Need a number, buddy?" he asked, holding out a number and four safety pins. "My brother couldn't make it -- take his."
I pinned it to my chest, and just like that, I was an official runner.
The gun sounded, and we were off. I was fine for the first couple of miles. Then I slowed down. Then my thighs started to chafe.
Grandma's warning rang in my ears. No way I could keep going.
Except a spectator at the side of the road spotted my problem, and tossed me a jar of Vaseline. A quick lube job, and I was all right. Ten miles. Thirteen. Sixteen.
I was going slower and slower, like the Tin Man in The Wizard of Oz when the rain starts to fall. People screamed encouragement, gave me drinks and orange slices. One guy tossed me a wet sponge to squeeze over my head, cool myself down.
After the 20 mile mark I was walking, then hobbling, and by the time I reached the 26.2 mile mark I all but crawled over the finish line.
I'd done it. It took me more than five hours, but I'd done it, and the handful of spectators who were there to see me finish cheered as if I'd won the race.
It wasn't until I'd hauled my throbbing body onto the train back to New York that I realized what an amazing day I'd just lived through.
True, I'd just gotten my ass handed to me in a legendary race, but I was elated, and not just because I'd finished.
No, I was elated because from the moment I awoke on marathon day, everybody I encountered wished me well, from the born-agains who drove me to the start to the leather-lunged strangers urging me to cross that finish line.
You don't get many days like that. It was enough to make a cynical New Yorker believe in humanity.
I'd eventually train properly and come back to run the Boston Marathon a lot faster.
I'd also eventually become a father. (You were wrong, Grandma!)
But that slow marathon of 1974 is the one I treasure. I think about it whenever things go wrong, whenever people let me down, whenever I let myself down.
And now, 39 years later, this unspeakable thing happens at the Boston Marathon. Just like that, a shadow falls over that perfect day of mine, and I realize a terrible thing.
These days, nothing is safe. Not even a memory.
Charlie Carillo is a producer for the TV show "Inside Edition." His novels "Shepherd Avenue," "My Ride With Gus," "Found Money," "God Plays Favorites" and "The Man Who Killed Santa Claus: A Love Story" are available for 99 cents on Amazon Kindle.
Follow Charlie Carillo on Twitter: www.twitter.com/charlie carillo