These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Ass Pull: After it's revealed that Matt is Robin's father, it seems obvious that Johnno isn't going to be Matt's son or else the show will have to answer to some seriousincest issues. Johnno is revealed to not be Matt's son, but it's at the end of the last episode with little foreshadowing besides a few lines and exists just to cover for the aforementioned reveal, which others might also consider an Ass Pull on its own.
Considering Al is the leader of a paedophile ring that uses date rape drugs, it is likely that Robin was raped again off screen during her blackout in episode 4.
When Robin first questions Matt about Tui's pregnancy, he boasts about how young he was when he first lost his virginity and jokes about Tui being "a slut like her dad". At the time, it comes across as macho insensitivity. However the final revelations about the paedophile ring and Matt's abusive mother make one wonder he was, in fact, abused as a child.
A minor one; Robin assumes her mother doesn't like Johnno because he's related to the unstable Matt, and that's also why her mother's last request is for her to not see Johnno. It is because she thinks he's related to Matt, but not because she worries that he's like his father or brothers; she knows that Robin is Matt's daughter and she's worried that she's watching her daughter commit incest.
Holy Shit Quotient: The series is in no way plodding, but the tension is pretty level and slow-burning, ramping up only when Jamie dies, and when Matt reveals he's Robin's father. And then comes the second half of the last episode. Matt's the father of Tui's baby! Or is he? Tui and her friends go missing! Robin shoots Al! The barista training is nothing more than a front for a sex ring, led by Al!
Narm: Johnno and Robin stripping down naked to have sex in the middle of the woods, while they're in the middle of an investigation, is pretty... random.
Squick: Robin and Johnno's sex scenes become this after the revelation that Robin is Matt's daughter. She even tries to seduce him, calling him her brother, though a shocked Johnno leaves. They're not really related, but damn.