That's gonna sound cliché, but D&D 3e, 4e, and 5e.
I was a 2E AD&D guy. I had my houserules, my homebrews, my Planescape books... I had refined and perfected 2E AD&D to my liking. Then people started talking about this new edition that simplified and codified everything. The more people kept talking about it, the less simple it started to appear, and the more bland the codes seemed to be. In addition, they had dropped the names of Baatezu and Tanar'ri, were allowing elves and dwarves to be paladins, were allocating wizards 1d6 hp per level, and giving clerics and druids 9 levels of spells! What the Baator! So I skipped it, mostly out of spite I think, like all the good movies I refused to see because everyone was talking about it (or worse, because of some actor that girls couldn't stop talk about). Like all good brooding, must-avoid-mainstream RPGer, I went on to play V:tM (the irony...)
Then, around the release of 3.5, I met a new RPG group and finally gave it a try (hey, it was either that or no RP!) and lo and behold, it was actually really good! And it was the houseruler and homebrewer's paradise! Apparently I wasn't the only one to think so because everyone and every game company started converting to 3.5.
After a good run, 4e was announced and I got very enthusiastic and had very high hopes. I subscribed to RPG news sites (ENWorld, what's that? Looks interesting...) and devoured every rumors and tidbit of information released. 4e would surprise me as well, but not in a good way. Apparently I wasn't the only one to think so because everyone and every game company started converting back to their own systems. So I skipped it, mostly out of spite I think, like many others.
Then, shortly before the release of 5e, I met a new RPG group and finally gave 4e a try (hey, it was either that or no RP!) and lo and behold, it was actually really good! They were playing it almost anime style, calling aloud their powers and whatnot. It was fun but short-lived as the rumors of 5e were everywere. So I went back to ENWorld and well, here we are.