Laziness or Fear to Think?

When we don't think through a problem completely, is it that we are lazy or that we fear that all the effort will still get us nowhere?

Let's say that it is laziness. If it is laziness, what can be done to overcome the laziness? Examine the benefits of the effort and motivate yourself more. Give yourself more reasons to be thorough.

Let's say it is fear. Courageously press forward, knowing that the effort in itself is the reward. The outcome may depend on factors that are not entirely in our hands.