sometimes God says no

I'm reading a book at the moment called 'Finding God in the Wilderness'

One of the points i read this morning was that God sometimes says no to the things you want.
Jesus said to His Father - “O My Father, if it is possible, let this cup pass from Me; nevertheless, not as I will, but as You will.”
And the Father - His Father - said no - because He had a greater purpose.

Sometimes God says no to us - even when it's something we want really bad, even when it's something good - because He has a greater purpose.