Such was the case with me. Many years ago I put in the back of my mind an experience my grandmother had with her sister when she was a young girl. She had told it to me a few times while I was growing up, and because I thought it was so funny, I figured it wouldn't be too hard to remember later to write down. Years passed and my grandmother passed away. Any chance of getting all the details correct by asking her directly about it had slipped away. I had always meant to write it down but never did. That memory, along with several others, lurk in the back of my mind waiting to be recorded and documented for my children and grandchildren to laugh about and possibly relate to when they read it.
I have recommitted myself to write down any past memories and memories of my childhood, good and bad, in chronological order or not, just for the sake of history. Who cares if it's in my journal or in someone else's, at least it's written down!