The devil knows where my weaknesses lay. He knows us better that we choose to assume that he does. If we do not have God as a part of our lives, we can not stand up to the devil and resist what he tempts us with. We have become wrapped up in our own lives that it is so easy for the devil to get us on his side. Without God we are nothing and we need to stop being caught up in our own lives and focus on what is important.
Finally, I realized reading this that we have come to the point where we rationalize and justify our sins. I know that there have been many times where I know what I am doing is wrong but I think to myself, "its okay, God won't stop loving me, I will still be a christian, I just wont ever do this again." Reading the screwtape letters I realized that this is the devil working in me. Each time that I allow myself to give into the devil is just making it easier for me the next time. If I continue on this path, I will lead myself away from my faith and this is a dangerous road. It is at this point when we being to ask where God is when we need him. We need to stop listening to the devil and start following God.