arduous but fruitless;do a hard but thankless job; waste energy and come to nothing; work hard but get little result
❍ 他的情绪不好，他觉得自己是～。He is in a bad mood,for he feels that he has been doing a hard but thankless job.
费力不讨好
do a difficult but thankless job;work hard but to no avail; make tireless but fruitless efforts
～的工作tough but thankless job;demanding but unrewarding job
费力不讨好fèi lì bù tǎo hǎo
指做了非常艰难的努力，但得不到他人的肯定。do a hard but thankless job, arduous but fruitless, be a fool for one’s pains