I hate taxes

I hate them. Mostly because they produce inordinate amounts of paperwork, all of which requires several forests of trees sacrifice their carbon-monoxide reducing selves. But I especially hate taxes this year because it has created a situation which served as a reminder of how poorly my grey matter is functioning.
We went to Saint Joseph, our previous hometown, for my husband's visit with Super Taxman. I had one job and ONE JOB ONLY whilst he was occupied, and that was to return our PO Box key to the post office. It's been in our possession since we moved in September and we've not paid the rent for the box since approximately June. My other intent was to see a few friends along the way, giving Boy 1 a chance to run around after sitting in the car, and giving my friends opportunity to gawk at Boy 2 since he's as cute as the bee's knees. BUT! My primary purpose of being in the car was to return said key. And I. Completely. Forgot.
My husband, being Mr Responsible, does not understand these kinds of mental bellyflops, and to be honest, this one puzzles even me. Can I still blame pregnancy? Stay-at-home-mom-hood? My lack of friends in Fillville, our new hometown, which makes me absolutely crave conversation with people I know and love? Argh. Needless to say, my blunder created an evening of icy relations and I have no explanation for myself. It is one more reason to hate taxes.