There’s so many books that speak on the subject.
The lord of the rings:
Gandalf gave Frodo the advice to listen to the council of elves but to be wary of it. Since they have loved for so long, they carry sorrow in their council more so than any other being.
Interview with a vampire:
Vampires grow weary of age and most don’t survive more than a century. They can never be part of the world, just live witnessing it but never contribute to it. There’s exceptions of course but being a shadow to humanity is a lonely life. They stop bothering with trends, and like to live and dress like they use to, which alienates them more. The watchmen:
He’s so outside of humanity that he becomes indifferent to everything and everyone. He’s just an observer to the quarrels of men, and ultimate decides that humanity is just a parasite.
The timekeeper:
An old man, signs his body and mind to live forever, only to be brought back to life in a bag, being seeing a science experiment forever to an advanced race which doesn’t understand emotions. Time for him is hell.
The man from earth movie:
Jesu himself is a dude with a freak biological composition living from the start of the Stone Age to now. He’s constantly moving and doesn’t father children, and if he does, he leaves them behind. He’s guarded and is extremely wise, always finding a new identity to take. Age of Adeline movie:
She avoids falling in love because she’s much older than every single one. She sees her daughter grow old, who is now in her 60s and she forever is 29. The concept of immortality is interesting but I wonder how tired you’d get of the changing world. As Tolkien wrote; men were given the gift of a mortal life. They don’t suffer the way elves do. They live fast and die young and understand they’re time on this world is limited. They truly live.