This is yet another contradicition that comes to my mind often, by personal experience, and somehow its likely others may have the same kind of self inquisition.
Its my personal opinion that everything has a purpose and the fact we may not understand that purpose doesn't change the fact that there is a reason for that given thing to exist - by extension its not farfected to give the same kind of pattern to human beings; there must be a purpose for us all - I don't mean something as obvious as having a job or such - role and purpose are not exactly the same (except maybe if any of you readers is a workaholic).
Purpose tends to hold a wider spectrum of meaning and it is not too difficult to realize that (even though it can take as many shapes and reaches as there are differences in each person).
The questioning though is in truth if purpose is a need or need is a purpose, in other words if people need a given task, position or function (again not limited to any formal work field) to feel they actually exist or if their purpose, or sense of self is simply that of feeling he/she is necessary or important to someone else.
My impression is that I belong to the latter side of this pendular movement - to me it is a (albeit strange to some) form of reassurance to know I am needed and that some sort of support is expected from me.
Others may feel more comfortable with a more self restrained, painstakingly defined function but that would most likely made me feel like Charles Chaplin in his ingenius "Modern Times" motion picture - workers were given greatly specific tasks and could do nothing more; its obvious that would have nefarious consequences to anyone's mental equilibrium, or at the very least lead into a towering wave of boredom.
I have full awareness that this may have been my strangest rant yet, but I felt I had to post something so I dug it all out from my head and put it here.
In closing,to me (and others I'm sure) its necessary to be necessary.