bred. Dogs that run with great speed use the flexibility of their back; a back that is too arched or too flat will restrict the dog's speed, and would be seen as a fault. Other major faults may involve temperament; "Aggressive behaviour is a serious temperament fault in a Lab." Whose fault is it? Interpretation of the standards Since dogs have enormous variation in their appearance, what is or is not considered desirable or undesirable depends on the individual breed's appearance and historical background (what kind of work it was bred to do). Individual breed clubs, whose members write the breed standard for their breed, decide which aspects of appearance and temperament that breeders should work towards eliminating in the breed. Those undesirable aspects of appearance and temperament are called faults. What constitutes a fault may differ from breed to breed. For example, an aloof and somewhat aggressive temperament might be suitable for a livestock guardian dog, but would be a completely unacceptable fault in a lap dog. Faults may be serious enough to require disqualification in a conformation show, eliminating the dog from winning a championship in conformation, or they may be minor, to be measured by the judge against the dog's good qualities. Some breed standards are punctilious in the extreme, spelling out exactly what constitutes a fault in every part of the animal, and the degree to which each fault must be penalized. Some are more loosely written, leaving more open to interpretation by the judge, or not describing an attribute at all, which leaves the matter up to the individual judge's opinion. Some breed standards states that a particular fault is to be penalized to the degree of the severity of the fault, leaving the exact determination up to the judge. Definitions which are open to human interpretation cause much ill-will at conformation shows when exhibitors disagree with the decision of the judge, despite the fact that the fanciers hire the judges and pay entry fees for the judge's opinion of their breeding stock. For example, most breed standards list a ‘scissor bite’ as the correct one. A level bite, an under-bite or an overbite may be considered faults, depending on the breed standard description. In a conformation show, the judge must decide the degree of severity of the faulty bite, and therefore how much the dog must be marked down in relation to other dogs.