Perfection
Perfection was a way of showing flawlessness and excellence. One who strove for perfection was called a perfectionist.
In 2267, Earth probe Nomad stated that its programmed function was to probe for biological infestations and to destroy lifeforms which were not perfect. These "imperfections" were sterilized. According to Spock, the dream of Nomad's creator, Jackson Roykirk, was to build a perfect thinking machine capable of independent logic. Captain James T. Kirk admitted that biological units were not perfect, but added that a biological unit had created Nomad, who claimed to be perfect. (TOS: "The Changeling")
While Amanda Grayson talked with Spock about Selek's behavior, Selek claimed that it was difficult for a father to bear less than perfection in his son. (TAS: "Yesteryear")