A number of people think of Satan as the personification of evil. Like Uncle Sam is the personification of patriotism, the devil is the representation of all evil. Or they think that people are evil and need no one to tempt them. But if they could, just for a moment, have the curtains of this seen world rolled back, they would believe.
Video Clip from Constantine - Chapter 12: 37:33 - 39:51 = 2:08
Now, that movie has some rather radical Biblical mistakes in it but much of what Constantine said in that dialog is true. Satan wants to influence us to evil. He and His minions are there to try and give us just the right or wrong nudge and it’s clear that the Devil knows about us whether we want to admit He’s real or not.