This Robert A. Heinlein science fiction story has never stopped being my absolute favorite.
Synopsis:
He sets the story up by telling about the first humans getting to Mars and promptly killing each other. The 20 years later humans land on Mars again and report that there were no survivors.
Shortly after, they report; "Correction, one survivor." During the doomed flight, one of the astronauts had cheated on her husband and got pregnant. When the baby was born, her husband, the doctor realized it was not his child, and killed everybody. The baby was the sole survivor. The astronauts also reported that Mars was inhabited, and that the Martians had raised the baby. They brought the young man back to earth.
The entire rest of the book is about this young man, a blank slate, learning about Earth and about humans. Because he was Martian through and through. He had Martian philosophy, Martian culture, and otherworldly Martian powers. Earth, and human culture, to him, were way beyond bizarre.
Since he was the sole survivor, by Earth laws, it made him the sole owner of Mars. Since they wanted to exploit Mars, they tried to assassinate him almost immediately. He made the threats instantly disappear. As he later explained: 'He sent them back to the foot of the line where they could eventually try their hand at life again'.
This is what that book taught me: What humans think is a shared convention which makes us think it bonds us, and makes us human. Isn't. Each of us have our own reality, and sometimes very little of it overlaps... and it is all made up.
I'm not going to say more. Read it. I hope you like it as much as I do. It shattered everything I thought understood and probably made me weird as hell. ๐