Continuing my latest binge of nonfiction self improvement audiobooks, I am currently listening to Nudge: Improving Decisions About Health, Wealth, and Happiness by Richard H. Thaler and Cass R. Sunstein.

In this book the authors discuss the concept of a “Planning Fallacy” in their section on “cognitive bias”.
Wikipedia defines a planning fallacy as “a phenomenon in which predictions about how much time will be needed to complete a future task display an optimism bias and underestimate the time needed.”
Well, I recently made quite the “planning fallacy” in relation to the pillow top I’ve been working on (and discussed in the post Pillow Popping with the Untethered Soul).
Using 2.5″ x 2.5″ scrap squares, I made an endless batch of half-square triangles (HSTs) to create a pillow top based on a pattern from the book Pillow Pop: 25 Quick-Sew Projects to Brighten Your Space by Heather Bostic.
I assembled the HSTs into this layout:

I thought I could sew all the half-square triangles together in an afternoon, no problem. Not just one pillow, I thought I might get a second pillow top done too (as I had a zillion HSTs).
However, as I began to sew them together, the pillow top started to significantly shrink and I had to add on more and more rows of HSTs to make the pillow top large enough for my intended pillow form:

This photo illustrates the difference of how wide I thought the pillow top would be compared to reality:

How my planning fallacy occurred: Based on the original pattern I thought I only needed 50 HSTs per pillow and I had nearly 200 HSTs – so I thought I could make FOUR pillow tops! However I discovered I needed like 196 HSTs for just ONE pillow and I spent most of the time I planned for sewing the HSTs together, to add on MANY more HSTs to make the pillow top wide enough.
What happened during my original planning? Well I never paid attention to the size of the original squares to create the HSTs in the original pattern (much larger than the squares I used, and if I was motivated I would get up from the sofa, find the book and give you the actual dimensions…).
As you can see from the photo above, I have half the pillow top pieced and I cannot believe how long it took me to just get half a pillow sewn together!
I will only be making ONE of these pillows. Next time I work with HSTs and a pattern, I will pay more attention and do better planning!
Postscript
On a more pleasant note, my lilac bush/tree is full bloom and my backyard smells wonderful!

During an intense Spring weeding session in my backyard this weekend, I paused for a “lilac break” and stood in front of the lilac bush and inhaled the incredible fragrance.
The scent of lilacs reminds me of being in my grandmother’s backyard in Pennsylvania as a young child. Lilacs smell like sweet childhood memories.