Mind Boggling

What makes an almost 10 year old act ungrateful and selfish?  It's beyond me.  She has been raised in an atmosphere of gratefulness as well as every Fruit of the Spirit.  It's talked about and examples are played out constantly.  They are drawn out plain and simple.  There is no question as to how one should behave in our family.  Yet, the attitude is still there.  Where does it come from?  Satan. 
But is the answer that simple?  How come the solution is so much harder.  And what is the solution?  Boarding school. The School of Hard Knocks, I guess.  Only I don't have the manual for that.  We've just been making it up as we go.