Grief and Loss - The Stages of Grief
Probably the most well-known of these might be from Elizabeth Kubler-Ross' book, "On Death and Dying." In it, she identified five stages of grief that a dying patient experiences when informed of their terminal prognosis.
The stages Kubler-Ross identified are:
Denial (this isn't happening to me)
Anger (why is this happening to me?)
Bargaining (I promise I'll be a better person if...)
Depression (I don't care anymore)
Acceptance (I'm ready for whatever comes)
Many people believe that these stages of grief are also experienced by others when they have lost a loved one.