In between junior and senior years in high school I took a college course in neurobiology, Did quite well at it. After a year of college I got out of the sciences and became a history major.

So that whole neurobiology course became a collection of useless facts.

Until...

Took Dad to the hospital after he got lost two blocks from home. They ran a series of blood tests, all normal. Then they sent him for a CT scan. I talked my way into the room with the technician and looked at the screen: two-thirds of Dad's right hemisphere was abnormal.

When they sent Dad for followup testing I distracted him by explaining the physics behind how an MRI works. Dad was an engineer and was so fascinated it didn't occur to him to worry. Then they sent him in and the technician rejected Dad because he was too overweight for the machine. The technician was calling for someone to take Dad back to his room and I pleaded. He's so cooperative. He almost fits.

They tried once more, wrapping Dad up and strapping him down, and got top quality images. The next day Dad had successful brain surgery.

tl;dr The information that seems useless might be useful after all.