As a general rule, courts are not in a position to balance the « proportionality » of the consideration, provided that the consideration is determined as « sufficient », the adequacy being defined as an exercise in legal review, while « adequacy » is subjective fairness or equivalence. For example, consent to the sale of a car for a pfennig may constitute a binding contract (although the transaction is an attempt to avoid taxes, it is treated by the tax authorities as if a market price had been paid).  Parties may do so for tax purposes and attempt to conceal donations in the form of contracts. This is called the peppercorn rule, but in some legal systems, the penny may be an insufficient nominal consideration. An exception to the adequacy rule is money, a debt that must always pay in full for « compliance and satisfaction. »     If the contract contains a valid compromise clause, the aggrieved person must apply for arbitration before filing an appeal, in accordance with the procedures set out in the clause. Many contracts provide that all disputes arising from them are settled through arbitration rather than arguing in court. « All contracts are agreements, but not all agreements are contracts. » This statement can be understood from the Venn diagram above. The agreements, which are enforceable under the law of the country, become contracts designated by the inner circle. The outer circle refers to agreements that are not contracts.
The shady part includes agreements that are not enforceable by law and are referred to as non-legal agreements. Some contracts are subject to multilateral instruments that require an unelected court to dismiss cases and require recognition of court judgments based on a jurisdiction clause. For example, the instruments of the Brussels regime (31 European states) and the Hague Convention on Judicial Decisions (European Union, Mexico, Montenegro, Singapore), as well as several legal acts relating to a particular legal area, may require the courts to apply and recognise the non-law and legal choice clauses and foreign judgments.