It doesn't just take seconds though. You have to locate the book bag, locate a pen, find the page and then write something.
It might not seem like much but actually remembering to do this in the first place is a real effort when life is complicated already.
When you have a toddler climbing all over you, no one wants the same thing for supper, no one can find any clothes, or be bothered to put the dirty ones in the washing - and then you realise you've run out of milk, or nappies, as well, or that it's swimming tomorrow and they need a suitable snack which you don't have in the house so you have to leave NOW and go in the shop...if there's a free parking space, that is.
So when life is actually pretty chaotic, it's just not that easy to do. Or important.
Our lives are a lot more organised than they were even a year ago. Things happen, it all goes upside down for a while and then it settles again, and then, when the dust has cleared, you might find you can remember to write in the book every day - and to buy milk, and so on, too. Sometimes.