There are many people who experience loss and do not know how to process it. There is no right or wrong way that loss should be processed. However there is a straight forward way and a complicated way. Both are equally painful and people cannot choose how they deal with a loss.
So why do people process loss differently? Depending on your experiences and how you relate to people around you will determine your response towards loss. A person who is more connected to their emotions may have an emotional response straight away towards a loss.
Whereas someone who has more difficulty with their emotions may not feel any emotion towards the loss. It may take sometime before they begin to feel anything. This can be described as a complicated reaction to loss.