Bob says to Lisa, "I will sell you my car for $1,000." Lisa nods and takes out $1,000 and gives it to Bob. Bob takes the money. Later, Bob realizes that the car is really worth more like $3,000. Bob sues to have the car returned. Bob can win his case by arguing that...

Hawkins, an 11-year-old boy, is injured when he accidentally touched a hot stove. The burn leaves him with an ugly scar on his hand. A neighbor who is a doctor, Dr. McGee, promises the boy and his father that he will give Hawkins a perfect hand if he will let him operate on the hand and test his experimental skin grafting procedure. However, the surgery goes badly and Hawkins ends up with a burned and hairy hand after the surgery instead of the burned hand from before the surgery. Hawkins sue McGee for damages under the agreement. How should the court measure the damages in awarding money from Hawkins to McGee?