A contract is an agreement which people want enforced by the
legal system. In exchange for the promise to pay for gasoline,
the service station attendant fills the car's gas tank Until
payment is made, the customer is liable for the payment. The
range of responsibilities or liabilities under contract is limited
only by your imagination of what people can reach agreements
to do. If the contract is valid (and not for an illegal purpose
like transporting street drugs) the law will enforce the liabilities
of the contract.
