Of these four, I have only read "Wicked" and I do not recommend it.
Of these five, I have read LOTR and Atlas Shrugged. LOTR is amazing but definitely difficult to get through, especially the beginning. Atlas Shrugged was just kind of ridiculous, but unlike the Fountainhead I actually managed to finish it.
A lot of people have this idea that you shouldn't abandon a book for the principle of it. They say that they don't want to "waste" the time already sunk into the book, or don't want to feel like the book "defeated" them. I disagree; there's nothing wrong with abandoning a boring book. I absolutely do not regret abandoning the Fountainhead and Wuthering Heights, but I do regret sticking with Wicked all the way to the end. As someone said, life is too short to read bad books.
Here's GoodRead's original article, which has a few more interesting infographics. One commenter quipped, "I look forward to abandoning Atlas Shrugged."
Are there any classic books that you couldn't finish?