Does the Pomodoro technique actually work or is it productivity theatre?

Both of your experiences are the well-known truth about Pomodoro: it's a genuinely good tool for a specific problem, misapplied as a universal law. What it's actually FOR: start-resistance and attention fatigue. '25 minutes then a break' makes dreaded work approachable and inserts recovery before your focus degrades. For grinding through problem sets, admin, revision — tasks you avoid or that drain steadily — it measurably helps people sustain longer total effort. Where it backfires, exactly as you found: flow states. Deep work on code, writing, or hard problems has a 10–20 minute warm-up cost; a timer that interrupts at minute 25 charges you that warm-up tax repeatedly. Breaking flow to honor a kitchen timer is theatre. The adjustment almost everyone converges on: treat the timer as a floor, not a ceiling. Use 25/5 to START; if you're in flow when it rings, silence it and ride — take the break when the wave drops naturally (often 60–90 minutes). Struggling days run strict tomatoes; flowing days run free. Also: honor the breaks (the technique fails most when 5-minute breaks become 25-minute phone holes) — walk, water, stare out a window instead. Verdict: not theatre; a starter motor being mistaken for an engine.