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Three Lines a Day: Why Logging Helps Parents Survive the Tantrum Years

By Leon MoriguchiPublished May 13, 2026Updated May 18, 20266 min read日本語版あり
Audience
Parents of children 18 months – 3 years

TL;DR

  • ·Tantrums are developmentally normal — 83% of preschoolers have them sometimes — but knowing that doesn't stop the cumulative grind; the missing tool is a way to manage your own cognition, not another technique
  • ·Three lines a day (a moment of crying paired with a moment of laughter) disrupts the peak–end bias that makes every evening feel like total defeat, and exposes patterns only your specific child and household can reveal
  • ·On the hardest days, one photo or one mood button is enough — the trick is keeping the bar low enough to clear when you're most depleted

Contents

  1. Lead
  2. What the experts say (and what it leaves out)
  3. Why writing it down works — three mechanisms
  4. 1. You notice that the anger was one moment, not the whole day
  5. 2. Patterns become visible
  6. 3. The things you said come into clearer focus
  7. A three-line template
  8. On the days you can't manage three lines
  9. What you notice years later
  10. Summary
  11. References

Lead

There is no shortage of articles about how to handle toddler tantrums. Validate the feeling. Offer choices. Step away if you must. All of it is correct.

And yet — if you still finish the day thinking I failed today again, the missing piece may not be another technique. It may be a way to pull what you are seeing out of your own head.

This piece argues for something at a slight angle from the usual: getting through the tantrum years by writing them down.

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In the memori app

The memori app keeps the day's feelings and events so you can look back and see what that stretch was actually like.

  • Mood is recorded next to what happened that day.
  • You can keep a diary about your child, with photos in it.
  • You can find photos with a phrase like "at the beach last summer."
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Next →Thirty Minutes Is Not Failing: What the Sleep-Onset Data Actually Show

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  • One Line a Day: Why the First Three Months Deserve Words, Not Just Photos
  • The First Smile You Remember: Where Memory and Medicine Disagree