Satan's greatest trick was convincing people that he doesn't exist !!
No, that's wrong. His greatest trick was getting God to not destroy him utterly, after his insurrection, like God destroyed lots of other things and people in the Bible (he clearly isn't squeamish or slow to rage), and getting God to give him his own kingdom to rule, and getting God to let him interfere at will in the lives of God's second recorded creation (mankind), and getting God to let him hang out in Paradise on Earth to tempt Adam and Eve (I mean, really, would you let someone who basically tried to kill you in your newborn's nursery?), and getting God to let him hang out with God himself (the bet regarding Job).
There are fairy tales that have fewer plot holes than the stories of God and Lucifer turned Satan. This is crazier than a fairy tale about Bush having Osama bin Laden be his Secretary of Defense.