We spend out lives saying hello and goodbye and living in between as if nothing will ever change. Our denial is complete and life-long so that we grieve each loss as if for the first time every-time we need to leave or be left (and it is always easier to leave than to be left).
The mark of maturity is to know that nothing is forever and not be paralyzed by that truth. To know the truth of coming loss but also to live with joy for what and who we do have while we have them. It takes a lot of energy to keep ourselves in the dark about the truth of change and endings. To embrace it takes less energy and actually there is, I think, a bit less pain in inevitable loss by doing so.