This Throwaway Line
In this week's episode, the one after the epic battle at Hardhome, Jon Snow brings back a huge population of wildlings to the Wall, and Alliser Thorne observes, "You have a good heart, Jon Snow. It'll get us all killed." What seems like a throwaway line may have more impact, though: Lyanna Stark was said to be a wonderful person, and Rhaegar (see the anecdote about Ser Barristan's account of him) may have also been. Their actions together incited Robert Baratheon's rebellion, displacing the line of Targaryen kings for the first time in years, i.e., getting them all killed.