If the parties have given different meanings to one concept, but one party is not aware of the adoption of the other party, it is bound by the adoption of that other party.  For example, a buyer and a seller enter into a chicken exchange agreement. The buyer thinks there is only one type of chicken called broiling chickens. The seller knows that there are two types of chickens, thirsty chickens and broiling chickens, and he knows that the buyer wants broiling chickens. In this case, the seller would have to provide the buyer with broiling chickens, even if the seller really intended to offer tangy chickens. A “basic presumption” is an assumption that deals with an essential fact of the agreement. Wrong beliefs must have such a strong influence on trade that the imbalance is such that it would be unfair to apply the treaty.  For example, at Renner v. Kehl, two vendors decided to sell leases on 2,000 hectares of undated land near Yuma, Arizona. The sellers were approached by a buyer who wanted to rent the land for the cultivation of Jojoba (ha-ho`ba), a shrub whose seeds produce precious oil, in the countryside.
The country seemed perfect for commercial production of jojoba. Both sides believed that there was enough water under the country that could maintain commercial production of jojoba. After the contract was signed, the parties found that there was not enough water to maintain these agricultural activities and the buyer therefore wanted to cancel the contract. The contract was cancelled because both parties in principle concluded that there was sufficient water to maintain production. The acceptance had a significant effect on the contract, as the parties entered into the contract only on the assumption that the purchaser could cultivate Jojoba on the land.  A limitation of this rule is that the party concerned can only avoid the contract if it has not taken the risk of making the error. On the other hand, if it is the nature of the agreement that a party takes a risk, the appearance of the expected danger does not constitute a “mistake” and does not avoid the contract. For example, if a land buyer knows that title insurance does not issue title insurance because it suspects some kind of title error, the subsequent discovery of a default is not a defence of error. The buyer was aware of the risk and took it care of. When the parties knowingly enter into an agreement without any relevant information, they cannot circumvent the contract simply because the relevant information affects one of the parties. For example, if a seller who has not exploited his land agrees to sell it and later discovers the presence of precious minerals under the country, there will be no reason to invalidate the contract. The seller knew or should have known of his lack of knowledge and his contractual agreement to sell the property takes the risk that he will sell something more valuable than he noticed.
 A contract may be “unacceptable” if the values exchanged are largely disproportionate.  Whether the terms are unacceptable is determined on a case-by-case basis. For example, when a contractor files an offer that is $50,000 less than it would normally have been because the contractor has miscalculated, a court may consider that unacceptable, making the agreement unenforceable. However, if the offer is only $5,000 less than usual, that may not be unacceptable.  The mere fact that a party is deceived does not nullify the treaty by nature, because it is Phelps/. McQuade, for example, found that overstaying its own assets to secure a financing agreement for the purchase of jewellery did not render the contract unenforceable. The buyer`s heritage status was not considered an essential element of the agreement, so the lie about it was not a substantial misrepresentation.  On the other hand, when a seller sells in a circle but presents it as a diamond, there is no question that would be considered material misrepresentation, because this untruth goes directly to the nature of the item sold.