What was the first edition of D&D you didn't enjoy? Why?
Hmmm...well, I can honestly say I've never played any edition that I didn't enjoy. The first edition that made me say, "Nope," was 3E. I'm pretty sure I would not have enjoyed that.
Remember back on day 10, when I said that my first gaming magazine was Dungeon, and how I loved it so much I got a subscription? I renewed that subscription several times, until one day the magazine that came looked...different...somehow. The cover art was still excellent, but the lettering was all weird, with sensationalized teasers of the adventures inside, as if they were the latest celebrity gossip! Exclamation points! I felt a little uneasy at this new style, but didn't panic just yet.
Then I looked inside. The horror. The horror.
All sorts of messed-up stuff in there. Nothing looked familiar, and the stat blocks! Sweet Flying Spaghetti Monster, the stat blocks! I didn't even recognize half the stats, and every monster had ability scores and skills. I tried my best to make sense of it all, to figure a way that I might use this material for my old classic D&D game, but I just couldn't grok this mess. The differences between classic D&D and AD&D are kind of like the differences between American English and British English. You probably have a preference for one or the other, but you could converse between them, and figure out what lorries and loos and lifts are from the context. Moldvay and 3E are completely different languages, perhaps with the same parent language, so you recognize a word here and there, but unless you actually learn 3E, you can't really make sense of it in Moldvay terms. As if that weren't bad enough, the adventures themselves had changed, perhaps to reflect some shift in the focus of the game system, and they did not engage my imagination at all.
That was it for me. Goodbye, Dungeon subscription, and goodbye, "official" D&D.