One should always perform mitzvos joyously, for there is no happiness greater than that of fulfilling God’s commandments.  It is said that God holds such joy in higher regard than the mitzvah itself.  One who performs a mitzvah without joy does so not out of love for God, but either out of fear of Him, or habit, or the desire to impress others.  One who rejoices in a mitzvah is surely motivated by love of God and His commandments. ~ R’ Eliyahu Kitov