They just don't understand...

Yesterday, Happy Hour with other graduate students:
Friend - "We were thinking of going out for dinner on Friday. Do you want to come?"
Me - "Sure, that sounds like fun... Oh! No, wait! I already have plans on Friday!"
Friend - "Really? what plans?"
Me - "I'm going to a yarn store..."
Friend - (interrupting) "A yarn store!?!" (look of puzzlement and amusement on my friend's face, as well as everyone else at the table) "You can't come to dinner because you're going to a yarn store? On a Friday night?"
Me - "Yes, they're having a trunk show. And I've never been to that yarn store..."

Ah, Muggles... they just don't understand. In the end, the dinner plans are not until 8-9pm and the trunk show is at 6pm, so I can probably do both and not have to explain further why I just can't cancel the "yarn store thing"... (I even RSVP'd! How am I going to win a door prize if I don't go? You know, good things come in threes and all that...)