Some think that GOD and Deities are policing human race. People do not commit sins due to fear that they will be punished.
Some others think that the supernatural powers exist only to fulfill their wishes. They also try to please by offering something.
This is the todays situation. Is this system existed before? At the beginning, ie during Vedic period, people worshipped ONLY NATURE and invisible power which is responsible for well being of Universe.
You need not worship Rama or Krishna or Shiva to be a Hindu. They took birth as humans just to give demonstration of how a life has to be lived. They almost succeeded in achieving a state where their consciousness bloomed. They were completely in synchronization with Universe. You can only follow them to find a good way in your life.