DragonQuest 3E. Character generation was a huge pain and the gameplay did nothing to salvage it. The whole thing was a needlessly complex monstrosity obsessed with verisimilitude to the exclusion of anything else. Literally the only game I got up from the table from and didn't even finish the session. And I've played some trash.
Rolemaster: OMG. I routinely embrace overly-complex games, but, just no. Of course, I tried it early on when it was the separate "_____ Law" boxed sets, it could've improved, I suppose.
You missed out! It was my main system for nearly 20 years.Couldnt even bring myself to try Chart Law
I am hesitant to say 5e D&D because I made several attempts to let it grow on me. But the fact is my first session playing in the Adventurers League sealed it for me. It wasn't the DM, however; he was a friend of mine and handled it well for what he was given. It was most of the players who showed up like it was a chore they had to do in order to get rewarded. They selected characters from a rotating stable of sheets with no names (i.e. "Barbarian 4", "Cleric 2", etc.). And despite early comments from the group being fans of Critical Role, almost everyone was reluctant to participate in any activity or play that didn't involve a roll that would lead to dealing damage to someone. FYI, the adventure was largely centered around a puzzle/riddle dungeon. The first time a creature appeared and offered a riddle, half the party charged and forced a combat.
It was then I decided that 5e (and public play in general) was not so appealing to me. What I had with 4e was no longer there, and it didn't seem it would be coming back.
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.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.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.