Favouritism
It mattered not to me that I was not my father's favourite. My half-brother, Fëanor, was the son of my father's first wife, Miriel Serindë; he was both wise and valiant, but cold and distant when he interacted with my mother and brother. I am second-born, the son of his second wife, and therefore I was loved second. All this never mattered until Fëanor accused me of usurping our father's throne.
'Get thee gone and take thy due place!'
His voice echoes and re-echoes in my head, the sting of the words wounding my heart and soul. If you so wish it, brother, then I will indeed leave your presence. Your words are unjust, your accusations unfounded, but should you desire it, you will have my forgiveness.
A/N: Not sure, this may be more about forgiveness than favouritism, but Valar above, it was hard to write! I could have done Faramir and Boromir instead, but they've been done a hundred times, and I've never written Fëanor stuff before, as far as I can remember.