What makes a Shetland sheep a "good" Shetland?

I have pondered this question, but have no glib, easy answer.

I think there are several answers.  First of all, a Shetland must be a good sheep. By this I mean the Shetland must have good ovine conformation, good health, good temperament and a good fleece. I think sheep with good bites, two testicles and at least 2 teats are only the beginning. Sheep also should display level toplines, width of chest and pelvis, length of loin, good pasterns, straight legs and hocks. A healthy sheep is parasite resistant and an "easy keeper", breeding early in the season, lambing multiple births without assistance, and ewes raising those multiple lambs without human assistance. A good sheepy temperament is an intelligent animal who learns the farm and farmer's routines and conforms to those routines without undue stress.  A bad sheepy temperament is either so flighty and fearful or agressive that injuries are inflicted upon the sheep, its lambs or the farmer and property during routine activities. I am not entirely sure what all should be included in a "good" fleece, but it should protect its sheep from the weather and be of some use to the shepherd.