Question: Only a small number of employment arrangements are governed by (relatively) complete contracts. One such area is professional sports, where a player's contract requires, among other things, that he show up for games, be available for interviews, obey certain rules when endorsing products, and so on. Most other workers are employed under extremely incomplete contracts, if they even have anything at all in writing. Why would both employers and employees often choose to operate under an incomplete contract rather than a more complete one?