What is "Consideration" and How Much is Required?
Generally, the courts will not reform a contract because one party made a bad bargain. Consideration is the value bargained for by the parties, and most decisions indicate there is no reason to inquire into a party's motivation for giving another party an incredible deal. In a famous legal quote, a single peppercorn was considered adequate consideration.
Having said that, consideration must meet other requirements. The consideration must be an exchange for the bargain in question; past consideration is no good.
Example: Suppose XYZ Corp. employs Dave under a contract for one year for $100,000. Six months later the president notes that Dave does not seem happy in his job. The president offers Dave $20,000 more to stay for the full term of the contract. At the end of the year, Dave asks for the extra $20,000. There is no enforceable contract for the extra incentive pay. Under the original contract, Dave was already obligated to work for XYZ Corp. for a full year. The extra pay is not supported by new consideration; Dave is not giving anything that he did not previously agree to.
But, if the $20,000 was offered to Dave to take on extra responsibilities or to work Friday nights, and he did, there would be additional consideration that would support the change to the contract.