George R.R. Martin, the author of the A Song of Ice and Fire fantasy book series, regrets that HBO’s Game of Thrones went past the books and led his characters down controversial paths. Welcome to the club, George, it’s been two years since that cursed finale, and we are all still very sorry things ended as they did.
Talking to Chicago’s PBS station, Martin said that HBO’s deal brought a lot more positive things than negative ones to his life. However, the “biggest issue” is that the TV adaptation of his magnum opus moved too fast and, eventually, went ahead of the books. By the time Martin struck a deal with HBO, four books of A Song of Ice and Fire were already published.
The fifth book, A Dance with Dragons, was released in July 2011, a few months after Game of Thrones premiered at HBO. Since then, Martin has been working on the next installment, The Winds of Winter, but we still have no idea when it will be finished. Now, Martin says that “looking back, I wish I’d stayed ahead of the books.
Commenting on the whole affair, Martin says:

When they began that series, I had four books already in print, and the fifth one came out just as the series was starting in 2011. I had a five-book head start. And these are gigantic books, as you know. I never thought they would catch up with me, but they did. They caught up with me and passed me, and, you know, that made it a little strange—because now, the show was ahead of me, and the show was going in somewhat different directions.”
Fans objected to the Game of Thrones finale so much that Martin has already promised, more than once, that his ending on the books will be different. And when will we be able to read that ending? In Martin’s words: “I’m still working on the book, but you’ll see my ending when that comes out.