And yet, if you promised ice cream a month ago, the child could probably recall every small detail, from what you were both wearing, the number of cars on the street, the song on the radio, etc.
Exactly why my kid remembers every gift I ever got him, but remembers nothing my wife gave him. It's the expectation, the wait. Nothing given at the exact moment the kid asked for is appreciated. Same goes for grown ups, not just kids. If you could buy everything you ever wanted at the exact same time you thought of it, that is a curse.