What word aptly describes a job or position that requires more than is reasonable from the person occupying it?
An example of usage might be:
"Today, John finally resigned his ___________ job."
To clarify, John is fully qualified to perform his duties and genuinely enjoys his work. Unfortunately, John's job at Evil Corp is unreasonably demanding. John's superiors have been frequently forced to increase his workload while lowering his pay. Long term employees are leaving the company in alarming numbers. John has a very loyal personality that has urged him to stick it through, but alas, John has reached his limit and must resign.