Consideration

A bargained for exchange between the offeror and oferee. Defined as either conferring a benefit or suffering a detriment. Consideration is the essence of what transitions a moral or ethical obligation into that which the law deems to be a legal obligation
or
What you get or give

Is the person willing to or looking to act based on the word of the other individual
In common law consideration could be nominal but now it has to be something of value and it must be reasonable

Preexisting duties and past consideration -
where 1 has a preexisting duty to perform in a manner a contract can not be made later with that as part of the bargain

Past Consideration
Son applied for college, made all arrangements, and then went to college decided he was short. paying is not an obligation because the son did not depend on it

Preclude a promisor from going back on a promise during the executory phase of an agreement
executory - to be executed
executed - already executed