We do attribute time-milestone quality to activities that otherwise would be simply dictated by unpredictable Nature. Breakfast at 8am, Lunch at 1pm, Dinner by 8pm; they already define how your day will be arranged, its activities, its different paces and flavours.
A slow started morning soon metamorphoses in a sprint-running sequel of wash, tuck, buckle, open, close, run, run, run. Lunch gives us a breath of fresh air, when we do not choose to keep on running, this time on a tapis-roulant perhaps. The slope leading down to 5pm is on sight. Dinner needs to be planned or ordered and then... Writing? Reading? Loving? Sleeping?