It's true that one can suffer and enjoy it. However, it would have to be bad for them to truly be suffering. It's not just a semantic point, in my opinion, but an important philosophical one. You won't get much argument from me on your utilitarian-style views, though I'd like to point out that it can be very difficult to actually account for the consequences that aren't obvious; the process is a messy one. I also wouldn't dispute the claim that suffering can plausibly lead to good things, but the best-case scenario is one in which there isn't the suffering in the first place, and those good things can be led to through good means.

The two aren't incompatible. Atheist is not believing, agnostic is not knowing; they're two different things.

They didn't say "There's no god" in their original comment. They said they didn't believe in one.

Feminism isn't sexist by definition. There are sexist feminists and double-standards that exist, however.

Compared to other species, pretty much any human worth calling a "person" is intelligent in some manner. Compared to other humans, it's not necessarily the case.

Actually, suffering is bad by its very definition. If someone finds physical pain pleasurable, they're not suffering when subjected to it.

I don't have to go hungry to know that starvation is bad. Likewise, one doesn't have to suffer to know that suffering is bad theoretically. In a Platonic sense, there could be a world in which suffering is an alien concept and all that is known is pleasure. In the current world we live in, I would concede that suffering may be an unfortunate necessity.

I can't tell whether or not you're being facetious (the curse of the anonymizing effect that textual media can have), but I'd like to let you know that matter isn't indestructible. Also, there's no good reason that I see to believe in a soul.

If a human achieved immortality, it would almost certainly not be through DNA. Besides the molecule's own inherent instability, it doesn't code for memories, experiences, exact physiology, or any potential method of ensuring absolute life.

The existence of xenophobia and conflict in the modern world is indisputable. There are less of either (per capita) right now than there ever has been in the past, ignoring small local fluctuations, however. Other than global warming and the increasing potential for self-annihilation (which is perhaps less than an external source of annihilation), the world is improving.

Would you rather live twenty years rather than eighty? Based on your reasoning, you should. I think that most of us would find such a proposition preposterous. The value of life is assumed to be inherent and in the individual quantum of time, not the infinite quanta in which we don't live. As for the problem you presented, it was answered in the very way you conveyed it. Upon a cursory examination of their position as an immortal, one could spot the potential to procrastinate, and thus correct for it. However, I think you underestimate the effect basic human psychology would impact upon the situation. Humans, like most other animals, like instant gratification and would seek it despite their longevity; moreover, immortality could present an opportunity to avoid some of the consequences of seeking this instant gratification, almost presenting the opposite problem.

Before I start, I will be functioning with a few assumptions about factors that were left ambiguous in the question. Immortality is never dying (not an assumption), but the legal definition of death is brain death. I don't think that anyone would count subsisting in a persistent vegetative state as "living" in the immortality sense, at least not if it's permanent and consciousness is forever gone; moreover, irreversible damage to the body over time would necessarily lead to an end of consciousness, so it isn't a viable objection. I think the best way to justify the existence of immortality in a case such as this is with some form of perfect regenerative healing or infinite resurrection.

With these out of the way, I will now launch into my justification of my advocacy for immortality. One of the initial knee-jerk responses many people have to the concept of immortality is that an individual faced with eternity would become terribly bored. There are several problems with this, however. First and foremost, I have serious doubt that a person from the 19th century that had retained their youth would find themselves bored amidst the astounding technological and social advancements that have been made over the last two-hundred years. Humanity advances at a sufficient rate that there will be novel stimuli for at least millennia yet to come. Second, if the said immortal gets bored, they have eternity for rekindled interest. Even if they go insane, there's an infinite stretch of time for them to be cured. Finally, this immortal person has a human brain, so it will probably be doing human processing. Anything else would be changing the bargain, so unfair. Since the human brain doesn't have infinite capacity, yet the person would perceive an infinite number of events, they will necessarily forget everything they ever experience, albeit after a long while. This presents the opportunity for everything to seem novel once more.

The second objection usually presented is the fact that all those an immortal person loved would perish around them. This is very true and very tragic; however, it is not a deal-breaker and is nigh insignificant when considered on the same scale as the life-span of the immortal. Most of us lose loved ones within our lives. When this happens, the loss seems unbearable. Over time, however, our sense of loss decreases as a natural part of the grieving cycle. Widowed spouses remarry, parents who lost their children have more, and children who lost their parents move on and perhaps adopt a new parent figure. "Yes," one might say, "but the immortal would become desensitized over time and form no new healthy relationships!" There are two responses I would have to this: One, when we see this happening in our lives, it is when lots of people die in close sequence that are close to someone else, not over the course of millennia, centuries, or usually even decades. When people have the opportunity to properly grieve and move on for a lost one, they can go one to form new healthy relationships. Two, even if the immortal became desensitized, they have eternity to re-sensitize, and if the former can occur, the latter should too.

The final and best objection that I hear is the claim that becoming trapped is a statistical necessity over an infinite period of time. This is very true, and the only response I have to that is that becoming freed from that trap is also a statistical necessity. Things like black holes and the universe's heat death are difficult to deal with, since they deal with absolute destruction.