I don’t think that goodbye, as a goodbye, is something that happens, there is always something (music, place, smell, landscape, etc.) that awakens our memory, the people, the pain and the joys.
I am sure that the “goodbye” is only a “see you soon,” although we often try to remove a painful experience from our memory. But our brain does not have a delete button, we can only store the thought and try not to think of it.
Our whole life and our experiences are archived in one place, waiting for “something” to bring them back to the present, whether we like it or not, we will relive those moments, whether they are happy or painful moments or simply… memories.
I have learned that the painful events are softened over time, their effect diminished, and thus life in presence becomes more bearable.
Some people claim that they have forgotten much of what happened to them in life and they try to live exclusively in the here and now. I think they just built barricades to make it harder for them to remember their past, but at some point, those memories will flood into everyday life again. Like the water behind a broken dam,
I think it is best to rationalize the painful or bitter experiences (which we all have) and give them the just measure so that they cannot happen again (if it was our fault), and to always use the happy memories to stimulate ourselves, to live without resentment or reproach, and to use every moment of our daily lives.
In the course of life, we leave and lose people, things or moments that we would like to keep. But it is not our decision how life goes, we cannot choose what to let go of and what to stay, we just must accept that nothing is forever and that we can use all events, even if they are painful. From them we can learn to implement what we came into this world for, to be happy and to help others in what is possible for us.
Without being a pessimist, I believe that I have already lost so much in life that I decided not to forget the future that remains. We should not say goodbye to what is yet to come, for it may be that what is happening is the only reason why we still remember what has already passed.