You and I are going to split $100. We each write the amount we demand on a slip of paper and then we show each other the demands. If our demands, added together, are less than or equal to $100, we split it as proposed and we both get paid. If the sum of our demands is greater than $100, neither of us gets jack.
Melencolia I
This famous 1514 engraving by the old master Albrecht Dürer shows a depressive genius.