For me, it may be that the toilet paper roll needs to have the open end away from the wall. I don’t want to reach under the roll to take a piece! That’s ludicrous!
That or my recent addiction to correcting people when they use “less” when they should use “fewer”
It’s learning over time, with proficiency being the area under the line. It’s describing having to learn a lot to achieve the same proficiency compared to something with a shallow learning curve.
Ebbinghaus didn’t integrate areas under the acquisition curve. He wasn’t a mathematical psychologist.