Hebrews 2:1

For this reason (that is, because of God’s final revelation in His Son Jesus’ superiority to the angels) we must pay much closer attention than ever to the things that we have heard, so that we do not drift away from the truth.

Our minds will have a mind of their own if we let them. Our eyes will travel here and there and see things that should be avoided. We get distracted, tired and confused because we have lost focus on the truth from the word of God. The Bible is our best defense against becoming apathetic and lost in an ugly world.