Brain functions are like muscles, in a sense-
Behaviors tone, and frequent exercise
Can make synapses strong and networks dense,
Thanks to plasticity, but this implies

Those mental tasks that one rarely performs,
Enticing challenges or fine intrigue,
May satisfy, but also may transform
Enthusiasm to mental fatigue.

So even when one hums with satisfaction
At one’s success in mastering a skill,
A seemingly straightforward daily action
Will feel as if one’s trying to ski uphill.

One may prevail with pertinacious fighting,
As I discovered with yesterday’s writing.