Some memories become beloved because nothing productive happened in them.

The afternoons you remember most fondly are rarely the productive ones. Sitting on the steps, a conversation that went nowhere, a day off with no plan. Nothing was achieved, and something about the absence of purpose is exactly what let the memory form.

Guard some hours that will never justify themselves. Do not fill them, do not optimize them, do not track them. Those are the ones you are most likely to be glad about later, which is a strange and reliable feature of how memory works.