Super Paper Mario was the big one for me this generation. When I first bought it, I only had a couple of Wii games, and I had been a huge fan of the Mario RPG series since the iteration on the SNES. So even though I knew it wasn't exactly like the previous Paper Mario games, I bought it. I wanted to like it so much, but I just couldn't. The RPG elements (the leveling system, the allies, the turn based battle system) were all either gone or only a mere shell of their former selves. The great humor and atmosphere that I loved in past games was gone. It was still good, but not what I had come to expect from the series. And overall, it was one of the games that made me so discouraged in the early days of the Wii.
I will always hate you Super Paper Mario, you sellout whore.