Most Seddie fans are just happy they got iOMG. But one thing still bugged me: What was the trigger for Sam's sudden behavioral change? Was it the arm wrestling match, or was Sam using Brad as a cover to try something new with Freddie? After pondering and discussing this on the Seddie Forum, a friend of mine gave me this response:
Semester projects are likely worth at least 50% of their grades, and Sam never worked on her own. She needed to pass. Since she gave Carly "torture" ideas for her project, but had no intention of being the torture subject, she had to piggyback. Brad made great fudge, so that was a perk of hangin' with the guys. Being around Freddie though made her guard drop more. Sam didn't expect the feelings she preferred to ignore would cause any problems, but she was in too deep and fooling nobody. Her feelings were genuine, but she wasn't ready to share them. Her ulterior motive to piggyback the project backfired. And thus the "180" is simmered down, because there is a classic Sam motive behind it all.
Not OOC, it all makes sense. It's so simple, I'm surprised no one else figured it out.