Game Of Thrones: 7 Dumbest Mistakes Made By Characters (And What They Cost)
3. Robb Stark Betraying Walder Frey
The Mistake: Instead of marrying one of Lord Walder Frey's daughters, Robb Stark decides to break their previous agreement, instead shacking up with a healer called Talisa.
What It Cost: A huge number of lives, including Robb's own. Walder Fray orchestrates the deaths of Robb, his wife Talisa, their unborn son and Catelyn Stark, dealing an absolutely massive blow to the Stark lineage in one evening.
If Robb had gone ahead with the marriage - something the Starks had actively agreed to - who knows what might have happened? Frey had no reason to betray those he was actively joining forces with, even if he was a thoroughly despicable guy. Besides, it's not like marriages in the world of Game Of Thrones are founded on love. They're power moves, there's no reason Robb couldn't have been reunited with Talisa at a later date.
Most costly of all, the Red Wedding granted the Lannisters total victory over the Starks, cementing them as the prevelent power in King's Landing.