Why Serve One We Never See? (John 14; LD 18)

One would think that serving the king of this world would be very beneficial.  We would see the king, we would be able to bring people to the king, and we could ask the king for favors. So, why is it good that Christ is in heaven?  Why would we want Christ to be in heaven if we are called to serve Him?  What is the benefit of Christ being in heaven as we sojourn through this earth as His royal subjects?