Perfect tender rule. For example, if I sold you 100 hammers and 90 of the hammers were fine but 10 of them were the wrong color, as a buyer you have the option of either rejecting all the hammers, accepting all the hammers, or accepting some and rejecting the non-conforming hammers." Why is this allowed? What is the social policy that is furthered by allowing a buyer to reject all based on the flaws of only a few?