As the saying goes, if you ask an author what they think of their first work, and they tell you they don't hate it with a red-hot burning passion usually reserved for serial killers, war criminals, and tax-collectors, they are lying through their teeth.
Seriously though, I had many terrible stories jotted down way back in my high-school days. I consider those the growing pains of a writer. You absolutely need to get them out of your system and learn from your mistakes, and without them, I wouldn't be where I am right now.
As for what was my capital "W" worst story... I suppose there are two separate candidates for that.
The first one was something I wrote with my best friend, and it was an absolutely nonsensical stream-of-consciousness style story about a foul-mouthed everyman who accidentally creates cold fusion by throwing a half-chewed piece of bacon into his old Russian microwave the size of a fridge. Then, while running away from the goons hired by the bank for defaulting on the mortgage of his exploded house, he accidentally stops the conspiracy of an dead Hungarian poet. He came back to life as a vampire due to sheer indignation over people butchering the language online, and he tries to destroy the internet by magically turning all the fiber optic cables into copper so that the Gypsies would steal them. Last part was inspired by a true story that happened in our town. It was unadulterated nonsense, and it wasn't even that funny, but back then we thought it was the best thing since sliced bread.
The other one is a much more complicated story, both in terms of its conception and the plot itself. So, it started with my friend from middle school, who was obsessed with the Prince of Persia games. We made a machinima-style comic out of them by taking lots of screenshots, and putting dialog bubbles and captions over them. All the main characters were pretty much inverted, with the main ones becoming foul-mouthed edgelords, while the villains were all helpful people who just wanted to save the world and feed orphans and such. It was crude, nonsensical, and not very funny.
Then a few years later another one of my friends started dabbling in RPG maker, and made a short game starring these characters. Then, over the years, the three of us made three more games of increasing size and complexity, but with the same crazy characters and juvenile humor. The plots ballooned, and so did the "lore", if you can call it that. And then I found out about visual novels and introduced the medium to my friend, and we had this crazy idea to make a visual novel using Ren'Py. The fact that neither of us could draw, code, or write a coherent story at the time didn't deter us at all, and so we started putting together a manuscript, with each one of us responsible for a separate character route, and holy crap, it was the best worst thing ever. As in, this was some prime-cut quality nanar stuff, and it was so deeply steeped in the "lore" we built up over the years, literally nobody could make heads or tails of what was going on in the story other than us, making the eventual prototype entirely worthless.
Oh boy, just talking about these things makes me want to try to find these for a good laugh.