[Multiplatform] Game Series you just stopped playing. Sonic is the correct answer, by the way.

Yes, Sonic is a great call--I've gone from unbridled enthousiasm for a new Sonic (Sonic 3 and Sonic & Knuckles especially had me delirious, still holding a spot in my top 5 favorite games of all time) to dreading the letdown of another poor game in my favorite franchise despite it all.

For me, it has to be almost all FPS's, but most importantly Doom. I grew up loving Doom and Duke Nukem 3D as a young teen. When Doom 2 came out, it vaguely coincided with my going to high school, where a network was in place. So we played a LOT of online multiplayer Doom 2. And I mean a lot. All we ever played was deathmatch on the first map, I don't believe I've even seen the rest of the game, but it was just amazing.

When Doom stopped and Quake made its way, I was still really into it, and when Quake 2 came out, I even joined an online clan, mostly playing Rocket Arena. When Unreal Tournament and Quake 3 Arena came out however, UT was the victor. I just found it to be so much more fun than Q3A, although I still enjoyed both. But starting from those games, I just didn't get into playing multiplayer FPSes anymore, and then I gradually lost interest in the FPS genre altogether. I tried to play and enjoy Doom 3, Quake 4, and the various Unreal and UT games, but I just couldn't get into it. I still like Half Life 2 though largely cause of the story.

Jam it back in, in the dark.