白玉微瑕

Explanation: The small white spots. Analogy some small shortcomings, fly in the ointment 　　Usage: The main predicate; as object, attribute; that fly in the ointment 　　Source: Tang Wu Jing, "Zhen Guan Zheng Yao fair": "The gentleman had a small, white cap micro flaw; little good villain, is one of the lead knife cut." Thesaurus:  a cloud on one's happiness