It takes many forms, one of which is having a loved one pass away and missing the opportunity to tell them your innermost feelings. The heartbreaking sadness comes with the realization that there are no second chances, that we will NEVER get to tell them all of the unspoken things that we never got around to saying.
I know that it happens to many of us. It has happened to me twice. In each case it was with completely different circumstances. The first time was when my father died of heart failure when I was 14. He was in decent health and it happened without warning. It was such a shock to the whole family.
So sure, unexpectedly losing a father was tremendously sad, but later that day it occurred to me that I will NEVER get to tell him how much he meant to me, and to tell him that he was my hero, and how much I loved him, and (for example) how much I appreciated all of the times he stopped what he was doing to answer my incessant questions about everything that entered my curious mind. (I have a very curious mind).
It haunts me to this day that I did not get to tell him goodbye.
This reminds me, I need to call my mother…