It can be really helpful to show the inconsistencies in someone's worldview. This can be a cool apologetics strategy, because Christianity may provide a better explanation for the world around us and the beliefs we hold.
But I find it really tiresome when Christians spend too much time pointing out instance after instance after instance of the intellectual inconsistentices in secular humanism. It begins to sound smug pretty quickly and it loses its freshness and force. Often the original goal is lost and it becomes a game of philosophical sledging, rather than true apologetics.
Worse still is when Christians assume it is really clever to point out any inconsistency in another person's point of view, as if this is pointing out some trace elements of secular humanism. Could it possibly be that all human reasoning is bound to have its inconsistencies? Do they have to be evidence of some fundamental worldview disaster?