良工心苦

liánggōng-xīnkǔ

[expert craftsmanship is the result of long practice and hard work; be done by a good worker out of deep-felt affection] 比喻精于制作或工于文字的人运思的费尽苦心

已知仙客意相亲, 更觉良工心独苦。 --唐·杜甫《题李尊师松树障子歌》