The most compelling characters...
The most compelling characters, IMO are Lindsay and Ken (Seth Rogan).
I just finished watching the series for the second time. It struck me that Lindsay made a conscious decision to hang with the freak crowd in order to avoid all the mind-numbing conformity of the typical high school experience. As an elite student, she would be expected to participate in all sorts of extra curicular activities, i.e. Mathletes. She would also have to deal with the issues of popularity, reputation, etc.
So, as Lindsay "hides" out with the little freak crowd, and bides her time waiting for high school to end, the other freaks are completely oblivious to her motives. The exception being Ken. I think he knows what she's doing, and this is why he is so cold to her. The fact is, he may be doing the same thing himself.
I say these things, because I did the same thing myself. I graduated HS in 1981, so this series really hits home. For me, high school was something I couldn't stand, and I was just waiting for it to end, and college to start.
"For dark is the suede that mows like a harvest"