Loss comes in waves and is difficult to describe. At first the loss is the only thing you can see, snapped tight as a ripcord around your heart. Each absent thing is delineated against the background of what is there until what is missing is the only thing visible. But in time, the loss loses its sharpness, diffuses. The vanished footprints you used to see so clearly trail off into many paths never taken.
There is the old ache of looking alone at something over which your eyes used to meet other eyes, but there is the new ache of looking at something new a first time and knowing you will never know what they would have thought about it, that it is guesswork from here on out.