You and your best friend commit a serious crime together. Prosecutors offer you a deal: testify against your friend and serve one year in prison, while they serve 15. Refuse, and you both serve 15 years. Your friend is being offered the same deal. What would you do?
A button gives you $50 million. Pressing it instantly kills two strangers somewhere on the other side of the world. There are no legal consequences, and nobody will ever know. Do you press it?