This.

Waterhouse, Gather Ye Rosebuds While Ye May (detail), 1909

APRIL 24, 1859

There is a season for everything, and we do not notice a given phenomenon except at that season, if, indeed, it can be called the same phenomenon at any other season. There is a time to watch the ripples on Ripple Lake, to look for arrowheads, to study the rocks and lichens, a time to walk on sandy deserts; and the observer of nature must improve these seasons as much as the farmer his. So boys fly kites and play ball or hawkie at particular times all over the State. A wise man will know what game to play to-day, and play it. We must not be governed by rigid rules, as by the almanac, but let the season rule us. The moods and thoughts of man are revolving just as steadily and incessantly as nature’s. Nothing must be postponed. Take time by the forelock. Now or never! You must live in the present, launch yourself on every wave, find your eternity in each moment. Fools stand on their island opportunities and look toward another land. There is no other land; there is no other life but this, or the like of this. Where the good husbandman is, there is the good soil. Take any other course, and life will be a succession of regrets. Let us see vessels sailing prosperously before the wind, and not simply stranded barks. There is no world for the penitent and regretful.

Henry David Thoreau