Whose Job Is It to Remember What They Wanted?

Wife takes 8 y/o to play ping pong, I take 6 & 3 y/o a bit later to meet up with them. We continue on our day. Before we met up with my wife, she asked me to bring her a snack. I made and packed the snack and put it in my bag. She never asked for the snack. I had it with me all day but forgot about it. Fast forward to the next day. She asks me if I brought it why didn't I give it to her. She never asked me for it.

So if you ask your spouse to bring you a snack, is it then their responsibility after meeting up with you later on to literally hand it to you and say, "Here's your snack." Wouldn't it be on the person who asked to then follow up about their own snack if they wanted it? Why literally ask about it the following day?