Since mid-July, McDonald's Philippines has transformed a single celebration into a weekly ritual — unlimited fries every Friday — drawing at least 350,000 participants each week in what may be a first for the global chain. The campaign is less a sales tactic than a deliberate attempt to embed a familiar product into the rhythm of daily life, turning a side dish into a reason to return. It asks a quiet but consequential question: can habit be designed, and can a brand become part of the week itself?