Expecting Grace?

Doing what is right can be such a struggle.  Why is that?  My 4 year old son has a relatively good handle on what is okay and what is not.  The need for constant explanation before receiving consequences isn't needed the way it used to be.  Discipline is administered more quickly.  Mercy is taken into account at times, but he tends to abuse it when it is given too much.
As I mature in my Christian walk I can't help but think God must view me the same way.  Mercy was something I needed A LOT more of earlier in my faith walk.  And though I may want it just as much now, it isn't always the best thing for me.
When I look at the big picture of what the Lord did for me - taking my sins at Calvary - I know I take that for granted.  The pain, physically and spiritually, that Jesus underwent is soooo much greater than I can possibly imagine!  I can remember doing things as a teenager and being grateful for the fact that God would forgive me... again.  If I had pictured Jesus having to die for me every time I sinned, it probably would have put a different light on things for me.
Willful disobedience is something that, as a parent, I will not put up with for very long.  God is my Heavenly Father.  How long will He, in his sovereignty, put up with mine?  While I can thankfully say that willful disobedience is something I very rarely choose now, I also wonder if there are choices in my life that I mask over with an excuse - things that I don't realize are disobedience to Him.  I imagine there are those areas in everyone's life.  My prayer is that the Holy Spirit reveals these things to me in HIS timing and that I am open to hearing from Him.  It can certainly be a painful thing.  That is why so many people say 'be careful what you pray for'.  However, if my life's goal is supposed to be honoring and living fully for my God, then how can I pray anything but that?