“[The effective executive is] forever on guard against the ‘impossible’ job, the job that simply is not for normal human beings.
Such jobs are common. They usually look exceedingly logical on paper. But they cannot be filled. One man of proven performance capacity after the other is tried — and none does well. Six months or a year later, the job has defeated them.
Almost always such a job was first created to accomodate an unusual man tailored to his idiosyncrasies. It usually calls for a mixture of temperaments that is rarely found in one person. Individuals can acquire very divergent kinds of knowledge and highly disparate skills. But they cannot change their temperaments. A job that calls for disparate temperaments becomes an “undoable” job, a man-killer.
The rule is simple: Any job that has defeated two or three men in succession, even though each had performed well in his previous assignments, must be assumed unfit for human beings. It must be redesigned.
(From The Effective Executive)