The Island of Dr. Moreau
How we cite our quotes:
And, as I had waded into the water, I remembered that if I were too hard pressed at least one path of escape from torment still lay open to me—they could not very well prevent my drowning myself. (11.7)
Every instinct a human has is aimed towards survival. Yet, presented with enough suffering, we will gladly choose death. Apparently there really is such a thing as intolerable suffering.
"See! I did a little thing, a wrong thing once. I jabbered, jabbered, stopped talking. None could understand. I am burnt, branded in the hand. He is great, he is good!" (12.37)
Sometimes people can be conditioned to enjoy suffering. No seriously, take the Ape here. When he could no longer talk, Moreau vivisected it back into him, and now he loves Moreau all the more for it. Ever heard of Stockholm Syndrome?
"It may be that save in this little planet, this speck of cosmic dust, invisible long before the nearest star could be attained—it may be, I say, that nowhere else does this thing called pain occur." (14.23)
Here's Moreau's cosmic (and shaky) defense for the suffering he causes. This suffering, really any suffering on the entire planet, is tiny on the cosmic scale. Completely insignificant. Of course, Moreau's grand ambition fails to recognize that what's tiny for the universe can be pretty huge to us.