Birthday present

Jenny gave Dave his birthday present in an intricate puzzle box, knowing he would never get around to solving it. But Dave knew how she was: he knew there would be nothing inside. So he solved it the day he got it, ready to fill with treasure and give back to her. Inside were two tickets to the gig that weekend, the one that had sold out before he even saw it. He didn't mention it, and neither did she. They just met at the venue, and he bought her a drink.