Dreams are a veil, a blindfold, a brainwash. Dreams fill your head with random images so you don't remember the truth.
When you sleep, you meet the impossible.
You meet the doctor who aborted you. You meet your killer (who apologizes profusely). You meet the thousands of children you could have had, and have to explain to every one why they weren't made. You have dinner with God, His husband, and His only begotten daughter. You play with the mechanical dogs who hold up the world, and fight off the soldiers of Entropy, who lust to devour the universe.
Each of these fascinating meetings are wiped away from your mind, and filled with a mishmash of adolescent sexual fantasies and absurdist fears. When you wake, you remember none of it, until the next night's meeting.
Every decade or so, you meet Death, and she offers you a deal.
The first time happened when you were still very young; Death took you to the bed of a dying man. He's ancient, and lying in a hospital bed, surrounded by his children, grandchildren, and great grandchildren.
"He's about to die," Death said as the sound of his heart monitor fills the room, "but I can take you instead. Choose who dies tonight: you or him."
You might scream and cry. You might curse Death and her cold heart, but, in the end, you chose to be selfish. If you hadn't, you wouldn't alive now. You woke that morning with the sound of a heart monitor wailing in a long, constant tone.
Years later, Death came to you again. This time, she showed you a woman on death row for poisoning her whole family and dismembering their corpses to cover up her crime. You watch as they screw her into a chair and tape her eyes shut.
"Do you want to take her place?" Death said.
You're obviously still alive, reading this, so you chose to watch as they burned her alive from the inside out.
Over the years, Death showed you many people on the verge of dying. Each time, they are younger, more innocent, more important than before: future Nobel laureates, pregnant women, and soldiers. You're given the chance to save the lives of artists, teachers, and children. You've always picked your own life, in the end, or you wouldn't be here.
One night, Death will finally find the one person you can't stand to see taken from the world: a child, your spouse, that boy you loved but never had the guts to ask out.
"Enough," you'll say. "Enough. You win. Take me."
And Death will bow.
"So, you've finally become selfless. I was worried you'd be immortal."
Just like every other night, you'll waken with no memory of the night, except for meaningless dreams. Maybe you'll get up, eat, play, work, whatever you'd normally do. This time, however, you'll have a strange feeling you can't explain. Somewhere, deep inside, you know you've done something noble.
That will be the last day of your life.