What makes Happiness by Arashi notable?

The song 'Happiness' became a significant hit, reaching the top of the Oricon charts and solidifying Arashi's status as one of Japan's leading pop groups. The album is notable for its infectious energy and appeal, contributing to the continued popularity of J-pop during this era. By 2007, Arashi was already established in the J-pop scene, having released multiple successful albums since their debut in 1999. 'Happiness' marked a significant moment as it was a lead single that showcased their evolving sound towards more contemporary pop influences while maintaining their bubblegum roots.