be in someone's shoes

Example: “I wouldn't want to be in his shoes when his boss sees that invoice.”

Origin: Rests on the observation that shoes are among the most personal things a person owns — shaped by one wear, uncomfortable on anyone else, and carrying the marks of exactly where their owner has walked. Occupying them, even hypothetically, therefore stands for taking on a whole position rather than merely imagining a feeling. There may be an older layer beneath the metaphor: in several Northern European legal customs a shoe was handed over as the physical token confirming a transfer of property or authority, and the Book of Ruth records a comparable practice of removing a sandal to seal a transaction. Whether the English idiom descends from any of that or simply reinvented an obvious image is not settled; the phrase itself is attested from the 1700s.