Elros & Maglor
I just try to think about why did Elros choose to be a human but an Elda who has immortality life.
The answer (for me) maybe a little coward: human race have received the best gift from the one : it is "death". And what comes after death is to forget.
Forget all the sadness and memories and just like falling asleep.
The truth about who destroyed his born country, the curse which followed behind the Feanorions, and Maglor's fate : leave them one day, and follows his brother to take back the Silmarils.
These memories are just too heavy, and no way to be stopped.
So here he goes, to become a human whose life is just in the blink of an eye, and left all the heart-broken memories behind.
(However his brother Elrond have to take the responsibility from Gil-galad’s last wishes, so he stayed and became a shield of the Middle-Earth)