Adaptation by Vague Recollection

[Aaron]

The sad thing is that the changes really took away from the gravity of Thorin's moral decay in the book.
In the book, the Lake-Towners - aside from the Master - treat the Dwarves as returning heroes and honour them with every courtesy. But in the movie, they seem more mean, more fickle, and an attempt is even made to justify Thorin's betrayal of them.

In the book, I saw no justification. Especially not when Thorin actually begins firing at messengers - an act which, by the standards of both the Medieval age and both Tolkien's and our own, is highly dishonourable. And, really, it's not "Dragon-sickness", or any such thing, I think it's pretty clear that it's his true character shining through - which is a far more interesting narrative to me than a sudden mood swing, and an even more sudden swing back.

Lake-Town, to me, felt as though they had been swindled by Thorin, charmed by all his pleases and thank you's and at your services, but ultimately as expendable as Bilbo himself.
I just feel that as the goal of the filmmakers was to turn Thorin into an action hero, they felt the need to introduce moral ambiguity about Lake-Town, so - at Thorin's eventual betrayal - you could think Oh, he has a point, really, doesn't he?
But come on, Tolkien's book was hardly painted in strokes of black and white, was it? There were hidden depths to be found, and I don't think those who made the movie saw them between the lines.