Tamaki Souh had been ignoring you his best friend, for Haruhi for a while now, it was making you somewhat sad/depressed.

Tamaki had noticed and attempted dragging you out of your funk inviting you to the annual Christmas Party they had even buying and sending you a dress to make sure you came, only to have you show up and still ignore you

Tamaki smiled with his usual charm speaking animatedly with Haruhi obviously happy "Yea that's my absolute favorite!"