Oh, that’s an easy one. It’s a matter of priority. To you, his Army serial number was very important to memorize; to keep in “memory” vs. “disk”, in computer terms. Right?
What you had for breakfast isn’t so important....so we sometimes reach a point where our brain can readily filter what’s important vs. what isn’t important.
Not a thing wrong with you. Still, that said, it’s never a bad idea to begin to exercise your short term memory. Lots of ways to do that. I even recommend games: dice games, dominoes (GREAT game for this), etc. Anything that exercises your short term memory.
So right.
When I was in 9th grade we had to take a vision test during phys ed. class.
I could tell that I wasn't going to pass but the last thing I wanted was to wear glasses.
So, I moseyed toward the eye chart and memorized the 20/20 line on the chart.
After more than 50 yrs. that line is still with me. D E F P O T E C.
Even stumbled through it backwards. Passed.