The Urgency of Discipleship

Luke 9: ⁵⁹ He said to another man, “Follow me.” But he replied, “Lord, first let me go and bury my father.” ⁶⁰ Jesus said to him, “Let the dead bury their own dead, but you go and proclaim the kingdom of God.” ⁶¹ Still another said, “I will follow you, Lord; but first let me go back and say goodbye to my family.” ⁶² Jesus replied, “No one who puts a hand to the plow and looks back is fit for service in the kingdom of God.”

What an incredibly cruel and heartless response to these two who are willing to serve, but have some legitimate things to finish!  Or is it?  Clearly Jesus knew of their respective situations, issued a call to service and made an example out of them when they offered excuses rather than obedience.  Verse 62 is quite a harsh rebuke for this lack of immediate obedience.  I've heard many opine that these were young men and the first meant to finish helping his perfectly healthy father run the family business until such time that his father grew old, died, he could liquidate the assets and support his life of discipleship.  There is no faith in such a worldly approach.  The other is even worse.  After all, they didn't have iPhones back in the day with which they could call or message the fam with a "hey I'm gonna backpack across the promised land with this Rabbi named Jesus."  It seems perfectly reasonable to run to the house, spread the good news of being invited to be a disciple of a rabbi, pack a change of underwear and a toothbrush, and hit the road, right?  
As Christians we spend most of our time doing everything EXCEPT serve.  We work, we recreate, we sleep, and if there is time we might drop by church.  Sometimes we're not even loyal fans of Christ.  Clearly a call to action demands an immediate response, yet there are so many very real responsibilities in today's world.  We've got families, jobs,  homes, cars, numerous accounts, etc, all requiring attention.  Isn't a reasonable response to Christ, "let me get myself in order and I'll be ready to serve?"   
Apparently not to Jesus.  He knows not only our history and current status, he uniquely knows our future.  These two were not willing to trust their future to His care.  Am I?  Have I been called to service and missed it because my house isn't in order?