you get it when you didn't need it

Usually when I go to fast food restaurants and I ask for a cup of hot water in a large cup, they usually end up just giving you a small cup. Today, however, I was kind of in a rush to get to SFX for the YAM gathering which starts at 7pm (instead of 7:30 as I thought) so I didn't need a large cup. I just needed some water to wash down my mouth. But the girl, maybe she was new, actually asked me if I wanted it in a large cup. It was a rare instance, so should I have taken a large cup even though I didn't need it? Oh well.