A lot of series that I used to like, but haven't cared for for a long time, including Resident Evil, Mario, Zelda, Mega Man, Mega Man X, and some series that I just never got into.
I'll agree on Mega Man X. After X4, I lost interest. I'll stick with Legends, and Battle Network.
I was always on, and off with Resident Evil. I'd get flustered trying to figure out something so I just chucked the controller, and turned it off. Sometimes when I was in the mood for it, i'd play it till I got tired.