Why does Game of thrones differ so much from a Song of Ice and Fire?

I watched yesterday the last episode of game of thrones The Laws of Gods and Men, and honestly for me that was the tiny spec that was needed to say that I had enough. I wonder why the are so many changes from the books to the series, to make matters worst pointless changes that some times even mess characters up like Stannis (in my opinion). I was okay with Khaleesi to have her dragons stolen as I thought that was made for increasing the viewers' suspense. But

• Why did they have to make up Locke for cutting of Jaime's hand and then sent him to the wall in order to get information about Bran? and then kill him


• Why the whole scene with Theon and Yara? (What's wrong with the name Asha ?)


• Why to even show Stannis at Braavos, who not only never been there, but at the time being (third book, blood and gold) he was at DragonStone (If I remember correctly, it's been a while since I've read it), doing nothing until Davos told him about the wall


• Finally why the whole thing with Jon and Bran at Craster's house

Answer

Unless you just plop the book in front of the camera and slowly turn pages for ten hours, any adaptation from a novel to a TV show is going to make changes both big and small.

They are taking a lot of subplots out, and creating a few of them.

Since Locke is now dead, there are no loose ends to this artificial subplot. He was simply created to avoid a bigger plot and then killed off.

As for Asha's name, the reasoning was that she would have been too easy to confuse with Osha. We're still waiting to see where her plot is going, though.

Since they took

Coldhands out of the show, and the whole magic door beneath the Wall, Sam was not sworn to secrecy anymore, so Jon was now aware of Bran being beyond the Wall.

The 'whole thing with Jon and Bran at Craster's house' was a device used to avoid unnecessary, non existing subplots that would bulk up the show.

As far as Stannis goes, I'm still waiting to see what happens.