Sorry you had such a terrible experience, but that seems to have nothing to do with the system. Have you considered trying a private game of 5e, with people you know, or is that not an option? Were there aspects of the system (unmentioned in your post) that also affected how you felt?
I think that was the whole point of this thread: games you left because of a bad experience, not because of the system itself. Experiences, however, will often sour our opinions more than practical logic. It's a common fallacy of human nature. That said, my own particular instance was more of a tipping point for me. I was hoping for a better experience that would provide some incentive to give this new edition another chance, at least as a player if not a DM. The result was a polar opposite, but it worked out (personally) for the best. Dropping D&D as my primary game of choice has allowed me to broaden my experience with other game systems that, quite frankly, work better on different levels that I find much more appealing.
Regarding specific aspects of 5e that affected me, you must first understand my perspective. I have played/DM'd every edition since 1st/Basic. I have never thought the d20 was a good design for a mechanic, but more importantly, I have always felt the Vancian-style spell system required more bookkeeping, accounting, and referencing than was necessary. Even though 4e was imperfect, it did address the latter and made everything easy to read and accessible without constantly needing to flip through books or online docs to see how some spell worked, or what abilities a monster had. It was all right there on the page. Along with other innovations that made being a DM easier than ever, I got spoiled on 4e design. So when 5e came out and reverted back to those old issues I had before, it was like taking a step backwards for me.
If I had never gotten a taste of what 4e could be, I would probably be on board with 5e right now. It is an improvement over the older editions, but I have already played this version before. And I recognize the personal short-comings that are still present in this edition. Even the storylines are little more than rehashed or re-imagined adventures I've seen printed and/or played before.
This edition is not for me, but I do not think it is a bad thing. I am still a fan of D&D. I still have my 4e collection (along with select books from previous editions). But I have also discovered more games out there, and have rekindled my childhood passion for Star Wars through the various games from Fantasy Flight Games. The narrative dice system from their RPG, however, is nothing less than an inspired bit of genius to me.