Finally, the parties must prove that they are both legally qualified. If, at the time of signing the contract, the parties are under 18 years of age, mentally incompetent or under the influence of drugs or alcohol, the parties are not deemed to be legally qualified. If the terms of the contract are uncertain or incomplete, the parties may not have reached an agreement in the eyes of the law.  An agreement does not constitute a contract, and failure to agree on key issues that may include elements such as price or safety may result in the failure of the entire contract. However, a court will attempt to make commercial contracts possible by interpreting an appropriate interpretation of the contract. h. . . .