Most of them weren´t that good actors
Everybody talks about how talented the cast were..... but honestly, I just started watching the show and most of them were awful. They may be very famous now, or talented..... but by watching the series you could never tell. They really took a leap of faith on most of them.
James Franco is bad, he does nothing but trying desperately to look cool, striking poses and not like in character, but as someone that really is vane, trying to pretend he is being vane for his role, which is bad acting.
Seth Rogen couldn´t even act at all. He only delivers a couple of quips now and then. I don´t even know why is he is credited or was casted, it appears that they knew he was too bad to have more lines.
Even people I thought were incredible actors, like Lizzy Caplan, she´s not that good here in F&G. I thought she was a natural when a saw her in Mean Girls, but here she´s so forgetable.
Rashida Jones, I really liked her in The office and Parks&Rec and she was plain bad here.
Shia Labeuf, he´s awful there. Yes, he was young, but like I said, I thought most of them were naturally talented but I see they really studied and improved themselves.
Segel was very decent, and even when I don´t really like Busy Phillips acting style (too loud), she really made an effort to carry a scene.
From the geeks, I can only call Sam Levine an actor. The others, even when much better than most freaks, well.... I don´t think I can see them in other roles.
I mean, Cardellini was what Michelle Williams was to Dawson´s Creek... or the Caire Danes of My So Called Life..... they didn´t even needed to talk to show the could act. She should´ve received 70% of the payroll herself just for carrying the show in her shoulders.