"For sin, taking occasion by the commandment, deceived me, and by it slew [me]."
Sin is deceptive: it tries to get us to think that we are missing out on something. "If you stop watching CSI, you're not going to know what happens to the characters." So What! "If you don't see this movie, you're missing out on some great entertainment." "You don't know what you're missing out on." Sin's lie from the beginning. Satan told Eve that she didn't know what she was missing out on by not eating from that one tree. He neglected to tell her all the negative aspects she was also missing out on, just as sin neglects the negative today. Sin doesn't tell us "CSI will make you have a cheaper view of human life, of marital relationships, of holy living in general." Sin doesn't tell us "That movie will strengthen your flesh and weaken your relationship with God." Sin doesn't tell us that we are 'missing out' on many things we would like to miss out on.
As we listen to the deceipt of sin, it dulls our senses for the spiritual. It dulls our appetite because we've filled ourselves up on spiritual junk food, and don't have the hunger for God that we should have. By filling up on junk, we can easily sabbotage our efforts at godly living. We can effectively cut ourselves off at our knees.
"The Fear of the Lord is the beginning of wisdom: and the knowledge of the holy is understanding" Proverbs 9:10