Immortality would only be a good thing for some people.
Most people who want immortality don't understand what it would be like to lose everything and everyone you cared about, only to find something else to care about, and then lose it again a couple decades later.
This would happen over and over again to someone who can't stand being eternally alone, and it would drive them completely insane. Most likely they would lose all sense of being and vegetate for the rest of eternity, nullifying any reason to be immortal.
In order for immortality to not affect you, you would have to be able to detach yourself completely from the rest of the world, in every way but presence. You could be there, do things, interact with people, but you could not form bonds beyond basic friendship, or risk insanity by loosing them over and over again.
That having been said, and not trying to sound like I'm puffing myself up, I believe I could stand immortality for the sole reason that, with the exception of my immediate family, I've been completely alone most of my life, and it doesn't bother me at all.
