Seneca isn't merely telling you to seize the day—he's asking you to abandon the fiction of a continuous self that stretches safely into tomorrow. Most people treat their lives as a single, unbroken thread they're always mending rather than weaving, which lets today become a dress rehearsal for a performance that never arrives. When you genuinely treat Tuesday as its own complete existence, you stop mortgaging your attention to some future version of yourself; a parent stops "getting to" meaningful conversation with a child once things settle down, a writer stops postponing the hard work of the first draft. The radical part of Seneca's counsel is that it doesn't promise happiness or accomplishment—only that each day lived fully in itself becomes its own justification, whether or not it leads anywhere at all.