Personal Meaning: a dosage guide

For some, the tragedy of the end of work would be that workers would lose their personal meaning.  My read is that this belief decries workaholism; meaning is available nearly everywhere: from the sublime to the absurd.  We are made better when we find our purpose in groups.  We are made worse when we find our purpose in Farmville.  And yet, in both cases we do find purpose.

There is an empirical question: if personal meaning is a good whose absence is costly, what is the minimum effective dose?  If the sole source of this is work, what factors influence its efficacy?  And at which dosage is work a poison?