Bad art, bad character design, cheap production and some of the same episodes as season 1.
Mind you, the first season was far from perfect, and like a lot of slice of life comedies, was rather dull at times (or hinged on things which are funny to elevens, but not us), but S2 was unwatchable. Giving Hosaka a five second cameo each episode? What the fuck.
GSG 2 doesn't even exist. The first series was perfect.