Which is worse: to take the time to say goodbye to a person, to a place, or to an activity, or to notice much later than, somehow, you stopped at some point to meet that person, to visit that place, or to do that thing?

I often notice things which I used to do and don't do anymore, and realize that there must have been one time which was the last one, and which probably didn't feel like it had any specific importance. Now, whenever I do something I haven't done for a long time and used to do regularly, I find myself wondering, "is this one of those last times which could have gone unnoticed?"