Oh there are so many bad/mediocre games I enjoy
Krusty's Super Fun House (SNES)
Clever puzzle platformer that nobody likes. I can totally see that it's really annoying, but I have very fond memories of it.
Beat Down: Fists of Vengeance (PS2)
Capcom brawler with light RPG elements. Is often mentioned together with Final Fight Streetwise and was universally panned. I like it
It's a bit like Yakuza, almost.
Suikoden Tierkreis (DS)
I am pretty surprised that this game is so hated but I understand that people were disappointed when it wasn't a proper Suikoden. Also, the voice acting is ATROCIOUS, especially the main character. But it's still one of my favourite JRPGs on the DS.
I'll think of more.