1. The Red Wedding
I'll be honest: I had a feeling there was going to be some kind of obstacle preventing Robb from enlisting the assistance of Walder Frey and his men - largely due to Robb's failure to keep his promise to marry one of Frey's daughters - but I didn't envisage quite what the Red Wedding had in store. All seems quite well as Frey seems to have forgiven Robb and everyone's tucking in to a feast. But then, we are given Catelyn's perspective as the band start to play The Rains of Castamere (a Lannister song). Suddenly anxious, she looks to Roose Bolton, and catches sight of the chain mail he is wearing under his garments, which of course he wouldn't need if he wasn't planning on violence. Catelyn immediately springs to her feet and shouts to Robb, but it's already too late. Talisa, Robb's pregnant wife, is stabbed repeatedly in the stomach, and she falls to the floor, dying slowly. Before Robb can get to her, he is sprayed with crossbow bolts. The entire Stark party are slaughtered. Even Greywind is killed in the stable. There are so many reasons why the Red Wedding is the most despicable moment in the entire show so far. Firstly, it's a betrayal; Walder Frey is supposed to serve Robb Stark. Secondly, the Freys take their allies in as guests and lure them into a comfort zone before murdering them. Thirdly, and perhaps most shockingly, the perpetrators evidently enjoy every moment, especially Walder Frey himself, who gleefully mocks the King in the North as he dies in front of him. In the next episode, the soldiers even decapitate Robb and Greywind, before attaching the direwolf's head to the man's body and parading it around outside on a horse. Quite possibly the most shocking moment in television history, and certainly in Game of Thrones, the notorious Red Wedding scene was even more horrifying than it was unexpected. As such, it takes its rightful place at the top of this list of heinous acts from Game of Thrones.