If Omega explained it was about to take out its super-scalpel and give me an incredibly precise lobotomy, which would take away some abilities of my mind, but not all, and there was nothing I could do to escape it, and afterwards Omega would poke the remnant of me with hot irons for a few days before killing me, but I could pay in advance to escape the hot irons, and the same offer was given to everyone, regardless of what Omega had predicted that they would choose...
If the lobotomy would take away my ability to appreciate complex forms of beauty, humor, and camaraderie, or my ability to form or comprehend English sentences, my ability to contribute to society, my ability to organize my experiences into narratives, my ability write and be persuaded by arguments like this one, my sense of a morality and inclination to act upon it, or my ability to design tools, I would still pay not to be poked with hot irons.
But if I was told that the lobotomy would take away my ability to suffer (And Omega said that by "suffer," it meant whatever familiar yet unidentified processes in my brain I previously attached that word to), I wouldn't care about the hot irons.
In the recent discussions here about the value of animals several people have argued that what matters is "sentience", or the ability to feel. This goes back to at least Bentham with "The question is not, Can they reason? nor, Can they talk? but, Can they suffer?"
Is "can they feel pain" or "can they feel pleasure" really the right question, though? Let's say we research the biological correlates of pleasure until we understand how to make a compact and efficient network of neurons that constantly experiences maximum pleasure. Because we've thrown out nearly everything else a brain does, this has the potential for orders of magnitude more sentience per gram of neurons than anything currently existing. A group of altruists intend to create a "happy neuron farm" of these: is this valuable? How valuable?
(Or say a supervillian is creating a "sad neuron farm". How important is it that we stop them? Does it matter at all?)