Many people believe that to do something well one must care deeply about it, and that not caring about a task or subject will result in a severe lack of quality, and possibly even a failure, of the task or objective. However, an overabundance of passion for something also results in a lack of quality, as judgement will often be clouded by your opinions for something. The people who recognize this will often decide that it’s best to have an emotional disconnect, and judge objectively so that one may complete or accomplish a task most satisfactorily.
I believe in the first opinion, as, from my own experience, if I don’t care about a subject or task (such as writing an essay about passion vs. detachment) then I have extreme difficulty in writing such an essay, or completing some other task, and I often end up procrastinating until I manage to work up the energy needed to do the task. When I do have an interest, though, then I can quickly belt out a nice and clean completion of a task, and I often enjoy doing it as well. Sometimes I even incite interest for myself by having a timer on my task, since completing a task within a certain time is of interest to me, and it can help center my attention on the task.
I do see the other point of view, however, particularly when viewing other peoples work that is noticeably over-passionate, to the point that the people end up making nonsensical decisions that only make sense from their own point of view. Therefore, while I believe passion is necessary to satisfactorily accomplish a task (especially in a timely manner) a certain level of objective detachment is also required.
The easiest way, I think, to be appropriately detached is to make a list of pros and cons, good and bad points, for every action and decision regarding the completion of the task. Obviously, this is somewhat cumbersome, but over time I believe it grows easier to imagine and automatically log different actions as pros and cons. While this can be manipulated by an overly passionate person, but normally it’s exceptionally obvious when they smudge a con into a pro, or vice versa.