Game of Thrones
It runs in the family
A majority of the novel is set around different families each trying to achieve the ultimate goal, to rule the iron throne. The TV series, however, portrays families such as the Starks and Lannisters bonding together, which, therefore, eliminated a plethora of charachters present in the novel.
Who's that guy again?
Robb Stark, who is declaring war on the Lannister's for executing his father has much fame placed on him in the TV series(he even weds) and much drama such as his followers leaving him and even an execution! This is surprising because in the novel very little is mentioned about Robb once he declares war on the Lannisters. This is important because it opens the viewers eyes to what is happening to Robb, which can only be guessed if you're only reading the novel.
Traitor or not?
The turning point in the novel as well as TV series is the execution of Ned Stark who is branded a traitor by King Joffrey. The TV series does a good job showing what false claims were made that made Ned a "traitor". The novel dives further into the claims, which adequately supports the fact that Ned is a traitor. This may have a major impact on viewers and readers because they may have a totally different view on the war his son started because of his execution, his daughters, and as well as Ned Stark's wifes futures.
Game Of Thrones-Eddard Stark's Death