Ascended Meme: As part of the fundraiser for the animated movie, one of the prizes was being able to finally take Atticus up on his offer about going out for pizzas with Troy.
Awesome Music: If you're a rock/metal fan in general, you'll recognize some of the songs in the show. Among the bands featured are: Anvil, Mouth of the Architect, Red Fang, Schoolyard Heroes, Blackguard, Children of Bodom, Municipal Waste, Danzig, Cult of Luna, Darkest Hour, Suicide Silence, Doomriders and more.
Best Known For The Ho Yay: A shockingly large amount of people were drawn to the show by the sexual tension between Todd and Atticus alone.
Draco in Leather Pants: Yes, Atticus is pathetic and only wants to be friends with Todd, but he's also a psychopath who revels in being evil, murders on a regular basis, and is overall a huge dick in general.
Ensemble Darkhorse: Hannah and Atticus are clearly the two most popular main characters, getting the lion's share of the plotlines in season 2.
Certain one-shot characters are also fondly remembered, such as Troy, the jock who manages to cram ridiculous amounts of Ho Yay in with Atticus over the course of 3 minutes.
Charlotte, Hannah's tongueless romantic rival is also quite popular. As is Straight GayWoobie Simon.
Eddie of the Metal Dudes is popular due to his catchphrase.
Fan-Preferred Couple: Surprisingly, Todd/Atticus has eclipsed all other pairings in popularity. Hannah/Todd is also more popular than the canon Jenny/Todd, due to Hannah's popularity and accommodating nature with Todd.
Growing the Beard: Season 2 has a much more compelling overarching plot and succeeds in making the entire cast more likeable.
Holy Shit Quotient: The second season finale reveals that Hannah's parents experimented on the Book of Pure Evil and the three metal dudes are apparently immortal magic-users. Not only that, but Todd expels the Book of Pure Evil from the school, Atticus becomes trapped in its pages and Hannah dies as a result of her connection to the book. At least until a new Hannah emerges from a cloning tank in the basement of the Crowley Heights retirement home.
Ho Yay: Todd has quite a bit with both of his male companions, but the truly staggering amount he has with Atticus stands out. Doubles as Foe Yay.
Atticus and Troy have about three minutes of screen time together, but in those three minutes the Ho Yay rivals Todd/Atticus in intensity.
Ship-to-Ship Combat: Inevitable. Todd/Jenny, Todd/Hannah and Todd/Atticus all have pretty large followings who are insulted whenever their couple is not portrayed as official in a fanfic. Todd/Curtis shippers also exist, but mostly as a joke and are more of a minority than the other three.
The Scrappy: Jenny is disliked for her "whiny" personality and getting in the way of Todd/Atticus ships.
It's also about her relationship with Todd: he's a Hopeless Suitor around her, when all she brought to the table was her looks (and many argued that Hannah was just as attractive as her.); her rudeness and hostility rubbed people the wrong way, and the fact that she was often portrayed in a more positive and competent light than the other main characters often got her labeled as a Mary Sue.
Squick: This series is not for the faint of heart, and features countless examples of gratuitous and over the top Gorn and Toilet Humor.
For fans who aren't fond of the Todd/Atticus ship, the idea of a man in his late thirties having a lustful obsession with a teenage boy can come off as this. This is the show's intended reaction to it, as all of the Foe Yay between them is acknowledged as creepy in-universe.
Tear Jerker: The death of Hannah, followed by Curtis' heartbroken declaration that he blames Todd.
Wangst: Played with, for laughs. Anytime anyone has an emotional issue, said person will run away crying out "Nobody understands me!"
Woobie: Simon and Leslie are two examples. He was bullied just for being gay and wanted acceptance and understanding for being different; Leslie was bubbly, but socially awkward and just wanted some friends. In both cases, the other students realized they'd essentially cast spells with the Book and kill them. If anything, it shows just how much of a Crapsack World the characters live in or how ruthless the Book is.
Atticus may be a massive tool, but his entire life is essentially one gigantic Trauma Conga Line.