The Ending of The Melancholy of Haruhi Suzumiya is addictive. I love it. Watch it:

Full Ending Theme Dance Without Credits

I think I only like it because I adore watching Kyon and Itsuki do that dance. Yeah. That sums up the entire reason why I watch it over and over – to watch Itsuki be way too happy and Kyon look miserably. I love them.