The anterior midcingulate cortex — the brain's tenacity structure — physically grows when you do things you actively don't want to do. It doesn't grow when you do hard things you love. It grows specifically from the friction of doing the hated thing. And its volume is the defining feature of superagers — people who maintain cognitive and physical ability into their 80s and 90s. The toilet paper roll isn't just a lesson in tidiness. It's neuroscience.