In many, if not most knowledge/office worker processes, the people are analogous to the machines in a manufacturing or physical process.
I've seen a lot of talk recently about the importance of attitude over other factors in employees and of course, this is nothing new. When it comes to performance of people in the different processes that occur in business, a better more accurate and powerful way to look at it is suitability. Suitability, typically encompasses the traits that underlie most of what determines a person's level of performance in a job or task. These include a person's key personality traits and natural tendencies, work and task preferences, motivations, decision styles and attitudes.
In knowledge/office worker processes such as accounting, sales, administrative processes etc., not only are the people often like the machines in manufacturing processes, but they have considerable choice as to when and how they do many of the tasks and often whether they do them at all. This is just one key reason why the underlying suitability traits of the person responsible for steps in a knowledge/office worker process are essential determinants of that process' performance.