Regardless of this, contracts and agreements are essential for many organizational businesses. Informal agreements do not meet the definition of a treaty. You might be happy with a simple deal if you know and trust the other party. You can also use an agreement instead of a contract if a contract doesn`t seem worth it. It`s unlikely you`ll need a contract to drive your friend to the airport for $10 for gas. A contract is a particular type of agreement that satisfies certain requirements to create legally binding obligations between the parties that are enforceable by a court.. . .