@confused1203
I actually dislike the way Sasameki Koto and Aoi Hana anime were made.
Not the animation or plot difference - but they're basically made anime only for the start of series. Including Girlfriends in that list, all of those mangas are pretty slow, they start with atmosphere, and relations, and ...there's not much plot happening. So having "first season" anime with hopes of later continuation is a bad approach.
If Girl Friends got 12-episode season, it would mean it's the only season it gets, period.