Let’s paint the scene.
Justin: How are we going to collect the gifts?
Maaya: I will pick them up.
Justin: I thought Trudy could because you couldn’t go until tomrorow.
Justin: So Trudy’s going to pick them up.
Maaya: Trudy’s busy. I will go pick them up.
Justin: But you can’t go until tomorrow, right?
Maaya: I will go tomorrow.
Justin: [Laughing] But they have to be picked up today. We actually wanted them yesterday. [silence]
Justin: So Trudy better go today.
It can be confusing at times or even need explicit effort to figure out this issue. Justin and Trudy discuss the coordination of gift pick-up and the suggestion that Trudy assist to meet scheduling demands. Maaya knows that Trudy has been feeling unwell and attempts to show empathy by offering to pick up the gift tomorrow; however, Justin focuses on getting the job done in a timely fashion. Neither is correct but both ideals and priorities are expressed.
On top of that, there’s a difference in the structure of English and Japanese, particularly in the forms of “yes” and “no”. In English, to be grammatical, a “yes” answer has to occur in an affirmative sentence and a “no” answer in a negative sentence. In response to “But you can’t go until tomorrow, right?”, Maaya must respond either,“Yes, I can go today,” or “No, I can’t go until tomorrow”. In Japanese, “yes” endorses what is already being said [i.e. that Maaya can’t go until tomorrow], and a “no” answer contradicts it.