In chapter 6 of The Princess Bride, Count Rugen states his main motivation for being a torturer is his obsession with pain and what causes it. After his first round of torturing Westley, Rugen tells Prince Humperdinck he's fascinated to see what happens. Will the mental or physical anguish cause the most pain? However, Rugen's true motivation isn't intellectual curiosity. He just enjoys watching others suffer. In fact, he thrives on it. He gives this away when he tells the Prince, "I feel quite invigorated."

Rugen soon realizes Westley is only faking screams of anguish he doesn't feel. That's why he doesn't say anything when the Prince tells him he thinks the torture is going well.

Rugen has been working for years to build what he believes will be the ultimate torture machine, and Westley's resistance to torture motivates him to finally finish it. Before he begins using the machine on Westley, Rugen tells him he knows he's been taking his brain away so he won't feel pain during torture, implying the machine will take this ability away for him. He also tells Westley he's leaving the Machine with him in his cage for 24 hours before the torture begins in order to increase his fear.

Rugen tells Westley he admires his courage and brilliance. He says he almost feels sad about destroying "the most altogether worthy creature it has ever been my privilege to meet."

However, what Rugen is really sad about is that he can't continue torturing Westley indefinitely because he poses a challenge to him, making it even more satisfying to cause him pain. He isn't pleased when the Prince takes over the machine and sets the pain setting as far as it will go, killing Westley in the process. As the Count is walking away, he thinks to himself that his death is a shame because "you just didn't come across victims like Westley every day of the year."