What is worth doing?

Peter Block, one of the most respected names in the field of organizational development, poses this provoking idea in his book The Answer to How Is Yes:

We often avoid the question of whether something is worth doing by going straight to the question "How do we do it?" In fact, when we believe that something is definitely not worth doing, we are particularly eager to start asking How?...Too often when a discussion is dominated by questions of How? we risk overvaluing what is practical and doable and postpone the questions of larger purpose and collective well-being. With the question How? we risk aspiring to goals that are defined for us by the culture and our institution, at the expense of pursuing purposes and intentions that arise from within ourselves.

Do you generally find this to be true, or do you have a different take on the usefulness or danger of the "How?" questions that permeate our interactions as organized people? For myself, Block's words bring to mind many occasions when I've seen potential ideas or great brainstorming derailed by premature "How?s" from those in government, the church, business, family, friends...and from myself...