Mackenzie's breakdown when Peter accuses her of drawing the dicks. After other people have had expectedly angry or unexpectedly funny reactions to being suspects, this is the first response that has been genuinely uncomfortable.
Dylan's visibly hurt reaction when seeing the doc for the first time and hearing everyone calling him an idiot or a fuck-up.
The ending, which ultimately reveals that after all of Peter's work, Dylan succumbed to everyone's low expectations of him and destroyed his own future anyway.
Season 2
The focus of Season 2, Kevin is treated like garbage by most of the school, to the point where it eventually cost him his only friends. Thankfully, he more than recovers by the end.
DeMarcus might be something of a Jerkass Woobie, but getting the glimpse at how trapped he feels by fake friends and his pushy dad, it's a tear jerker to hear him say that he was scared nobody actually liked him or cared about him, which is how the Turd Burglar was able to get him and manipulate him. As DeMarcus seems to be the envy of everybody in the school and too cool, it really demonstrates how everyone is in the same boat at school.
