Fr. Ray Blake has recently put up an interesting post concerning the devil, posession and exorcism.
One of the main themes seems to be the tendency not to notice the diabolic in the world because it seems trivial and commonplace. This is, of course, a trick of the devil: very few people would deliberately seek out and follow the obviously evil, but it is very easy for all of us to get taken in by those little things that 'chip away' at our relationship with God, or, put another way in the words of Pope Francis, which Fr. Blake quotes several times, 'If we are not praying to Christ, we are praying to the devil'.