I recently read a book called “100-Day Challenge” by Ami Otsuka, and as soon as I finished it, I found myself thinking:

“Wait… what did I even do over the last 100 days?”
Probably nothing more than trying (and failing) to protect my pudding from other family members.
Anyway, today I’d like to casually share the insights and lessons I learned from this inspiring book about how an ordinary college student expanded her world in just 100 days.
- From Regular College Student to Global Creator—Powered by ChatGPT
- Mind-Blowing Stats: 10x the Productivity of a Professional Programmer!?
- Wait, She Used ChatGPT More Than 10 Times Per Hour?
- From “Programming is Pain” to “Programming is Play”
- Transforming Your Life Through Documentation
- “Consistency is About Enjoying the Habit”
- In Closing: What Will Your 100-Day Challenge Be?
From Regular College Student to Global Creator—Powered by ChatGPT
Ami Otsuka, the author, was just an average university student.
One day, she decided, “Hey, I’m going to make a game,” and began posting a new game every single day for 100 days on X (formerly Twitter), using ChatGPT for support.
And what happened as a result?
- Her followers skyrocketed
- She got opportunities to present at academic conferences
- She published a book (!)
- Her work gained international attention
Honestly, it’s like a modern-day Cinderella story—except instead of a fairy godmother, she had ChatGPT.
Mind-Blowing Stats: 10x the Productivity of a Professional Programmer!?
One of the most shocking details from the book:
Over the course of 100 days, she wrote more than 50,000 lines of code.
For comparison, an average professional programmer is said to write about 1,000 lines of code in 20 working days. So in 100 days, that would be roughly 5,000 lines.
Yep. That means 10 times more.
It really made me want to ask ChatGPT,
“Is this normal for a human being?”
Apparently, when you combine AI and focus, the results can be extraordinary.
Wait, She Used ChatGPT More Than 10 Times Per Hour?
Even more surprising:
- 8,123 prompts over 100 days
- That’s about 80 prompts a day
- If she worked 8 hours a day, that’s roughly 10 prompts per hour
That means she was sending ChatGPT a message every 6 minutes!
At that frequency, it’s no wonder innovation was happening left and right.
From “Programming is Pain” to “Programming is Play”
This was the part that moved me the most.
Programming is often seen as tough, tedious work. But she turned it into play—a fun, creative process—by making games with ChatGPT and posting them on X.
It wasn’t just learning anymore; it was sharing, connecting with others, and feeling proud of what she made.
She even picked up English naturally by participating in international gaming communities during the pandemic.
When learning becomes fun, you unlock your full potential.
Transforming Your Life Through Documentation
Another brilliant aspect of her journey was how she documented her learning process on X.
It wasn’t just about grinding through code—it was about sharing the how, not just the what.
Posting your progress publicly helps you stay motivated and lets you reflect on how far you’ve come.
Honestly, it’s a super practical technique I think anyone can use.
“Consistency is About Enjoying the Habit”
The final chapter of the book left me with a quote that hit me hard:
“Consistency isn’t suffering—it’s about enjoying a habit.”
Ouch. That struck a nerve.
I used to think consistency meant sheer willpower and grit.
But now I realize it’s about creating a state where you naturally want to keep doing something because it’s fun.
That’s the mindset I want to bring into my own life.
In Closing: What Will Your 100-Day Challenge Be?
100-Day Challenge is a book that reminds you how a simple idea can lead to a completely new path in life.
After reading it, I’ve been thinking about trying a “100-Day Ab Roller Challenge.”
(Although, to be honest, my abs are already trembling after day two…)
So, what’s your 100-day challenge going to be?
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