The Fades/YMMV

Ho Yay: Mac and Paul, particularly this conversation from Episode 3.

Mac: I could have been naked!
Paul: I've seen you naked.
Mac: I could have been masturbating!
Paul: I've seen you masturbate.
Mac: *disturbed* When?

Paul: On the school trip to Calais.

Mac: *With horror* You... were awake.

Tear Jerker: Jay.. oh Jay. In fact, the whole last episode was a mixture of a Crowning Moment of Awesome and Tear Jerker.
Moral Event Horizon: While Neil had been getting ever more unstable and radical as time went by, as exemplified by his torture of Natalie, he irrevocably jumps off the slippery slope when he kills Jay to motivate Paul to attack John, promising to do the same to the rest of his family if he refuses.