They say that the largest disruption in life is when we retire from work. After 40 years of doing the same thing, we lose our sense of who we are, our routine, our titles. Perhaps it is part of the grief and what makes a good retirement, is being able to go through the grieving process and come to terms with the loss.
I think that we should practice grieving and gratitude throughout our lives, because inevitably, we are going to face loss and, we should be thankful for what we have.
Yes retirement is difficult. A change that big after 40 years is really difficult and some times it leads to depression especially if it happens unexpectedly ( accident or health issues ).