expression
zeal blinds one to the bigger picture
Proverb warning that single-minded pursuit of a goal can make one overlook dangers or the broader situation. Literally: 'The one who chases a deer does not see the mountain.'
利益ばかり追いかけて、会社の評判を落とすとは、まさに鹿を追う者は山を見ずだ。
Chasing only profits and ruining the company's reputation is a perfect example of zeal being a bad servant.
Similar proverb about missing the forest for the trees, but 鹿を追う者は山を見ず emphasizes being blinded by a specific goal rather than focusing on details.
A traditional Japanese proverb. The exact origin is uncertain, but it uses the imagery of a hunter so focused on chasing a deer that they fail to notice the mountain (the surrounding environment).