Sometimes those moments of really living are grand expansive scenes and sometimes they are private moments when a series of mental tumblers fall in place. Regardless, the common thread of all "Really Living" moments is that they create a dent in your chronometer - a notch in the thread of time running through your brain and hence expand the sense of time spent here on earth. Here's a short but elegant summary from friend Ira Friedman of a "Really Moment" from his memories:
------------ In the 1980’s I was in charge of the paper pickers in a state park in NY. It was my job to scan the beach on a Monday morning to see where trash had to be picked up. It was a hot summer day where the temperature was supposed to reach 100º. At 7AM I was walking the beach. It was 78º with a wonderful breeze blowing in my face. I was wearing one of the original Walkmans and listening to Bob Seger singing "Against The Wind." I soaked in that moment and that sensation and vowed to remember that moment so that on any given day when the weather was crappy I would call to mind that experience. In a small way that is what i believe you are saying about "Really Living" - where memorable moments emerge in a spontaneous way that your mind latches onto.