The boss's torrent of criticism left him completely lost.
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culture
Northerners (especially Beijingers) traditionally orient themselves by cardinal directions (north/south) rather than left/right. 'Can't find north' literally means losing your sense of direction, and idiomatically extends to losing your mental footing in any situation.
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Colloquial. Often used humorously or self-deprecatingly. The potential complement 着 (zháo) is the Beijing-flavored variant; some speakers say 找不到北 (zhǎobudàoběi) instead.