Anything that is supposed to be in a complete state, but is not yet complete, does not really exist at all. Judaism is a structure of connecting to Hashem, not just a collection of mitzvos. Blessing over a whole item precedes a larger incomplete item. Greatness is measured by seeing things through to the end. The 'building' of Avraham Avinu (our Patriarch) was only completed with his tenth trial. We ask Hashem to help us serve Him with a whole heart – to fulfill our potential. Our lives are worthless if we only make our life service of Hashem as incomplete 'pieces'.