This is the difference between having visitors out of obligation, and welcoming people out of love. In both cases, we want their time here to be the best possible, with everything ready for them when they arrive. However, there is a world of difference between getting ready in a panic, and joyfully working to make our guests welcome.
Christ wants us to be happy for His arrival. This season is all about examining our lives and looking to improve them, but we need to do so out of love, not obligation. After all, we want do not want Christ to feel like He is causing an imposition by joining us in our lives, but that He is welcome to do so.