If I was immortal eventually I would become a wise man of sorts, sharing the wisdom that comes with centuries of life experience and warning people when they're about to make a big mistake. Just think about that. World leaders drinking from your fountain of knoweldge. Past conflicts may never occur again!
You would be around long enough to notice evolutionary changes of animals. Tehnology would advance beyond our current comprehension right before your eyes! Imagine going from gas guzzling land cars to flying flying cars that run on practically nothing!
If you can learn to accept death the main disadvantage of immortality is gone. The human race is always advancing and there is more stuff to do on Earth, and beyond, to keep you busy for a long time.
However, there are some things not specified with this gift of immortality. For example, would you keep your youth? Living forever would be a lot less fun as an old man. Another thing, when doomsday/the extinction of the human race comes will you survive that too? being the last living thing on Earth would be awful.
I would like to write some more but I should really get to sleep now. :tired: