The Red Wedding was painful. But there was a lot of hints. I love the Starks, but they were making mistakes. And it was kind of repetitive that honor and loyalty was hurting them.
I kept telling yourself "man, if only the Lannisters were going against people that were willing to stoop to their level, somebody who will do whatever is necessary".
Here comes the Red Viper from Dorne. In someways, Dorne has some similarities to the North. It's a pretty open land and they are different from the other kingdoms. And they didn't really have anyone involved with KL. But, Oberyn gave the impression that he wasn't going to let honor get in the way. Basically, he didn't have Robb's and Ned's weak traits for the game of thrones. Oberyn was different. And he gave off a vibe that said "Oh hell yes, we have good guys that are willing to play Tywin's games and more".
Red Viper and Tyrion make some conversion before the dual and how they are going to put Myrcella on the Throne. Ok sweet. Sounds like a good plan.
He's beating the Mountain. He's the better fighter. But it wasn't honor and loyalty that killed him. I wouldn't even say it was cockiness. It was the Red Viper hastily trying to do too much by beating the Mountain while trying to get a public confession.
Well damn... Just like that, our dreams of seeing a house getting vengeance on the Lannisters was done. Tyrion's throwing up was basically how I felt (I really wish they did that in the show).