I think curse. Douglass Adams cam up with the best example of why being immortal would suck.
"Wowbagger The Infinitely Prolonged
Wowbagger The Infinitely Prolonged was - indeed, is- one of the Universe's ver small number of immortal beings.
Most of those who are born immortal instinctively know how to cope with it, but Wowbagger was not one of them. Indeed, he had come to hate them, the load of serene bastards. He had his immortaility inadvertantly thrust upon him by an unfortunate accident with an irrational particle accelerator, a liquid lunch, and a pair of rubber bands. The precise details are not important because no one has ever managed to duplicate the exact circumstances under which it happened, and many people have ended up looking very silly, or dead, or both, trying.
To begin with it was fun, he had a ball, living dangerously, taking risks, cleaning up on high-yield long-term investments, and just generally outliving the hell out of everybody.
In the end, it was Sunday afternoons he couldn't cope with, and that terrible listlessness that starts to set in at about 2:55 when you know you've taken all the baths you can usefully take that day, that however hard you stare at any given paragraph in the newspaper you will never actually read it, or use the revolutionary new pruning technique it describes, and that as you stare at the clock the hands will move relentlessly on to four o'clock, and you will enter the Long Dark Teatime of the Soul.
So things began to pall for him. The merry smiles he used to wear at other people's funerals began to fade. He began to despise the Universe in general, and everybody in it in particular.
This was the point at which he conceived his purpose, the thing that would drive him on, and which, as far as he could see, would drive him on forever. It was this:
He would insult the Universe.
That is, he would insult everybody in it. Individually, personally, one by one, and (this was the thing he really decided to grit his teeth over) in Alphabetical Order.
When people protested to him, as they sometimes had done, that the plan was not merely misguided but actually impossible because of the number of people being born and dying all the time, he would merely fix them with a steely look and say, "A man can dream, can't he?"
And so he had started out. He equipped a spaceship that was built to last with a computer capable of handling all the data processing involved in keeping track of the entire population of the known Universe and working out the horrifically complicated routes involved. "
So yeah. Boring.
