die Sisyphusarbeit
noun: Sisyphean/never-ending task
This proverb is used to refer to ‘hard work that is pointless or futile and never leads to the goal’. It comes from Greek mythology, named after Sísyphos (Σίσυφος), who was condemned to eternally roll a boulder up a steep mountain in the underworld, as the boulder kept rolling back down into the valley before he could reach the top.
[IDIOM] Es ist eine Sisyphusarbeit. = It’s like painting the Forth Bridge.
Fast schon Sisyphusarbeit ist es, wenn man an einer Schule arbeitet und die Schüler nicht kooperieren. = It's almost Sisyphean work when you work at a school and the pupils are not cooperating.
Franz Stuck, 'Sisyphus' (1920). Photo: masterpieceart.net via Wikimedia Commons