Since ancient times people have been trying to get more flexible.
We understand from many ancient text discovered that good martial artists require a certain amount of flexibility to move with nimbleness, agility. That is also a principle shared among all dancers, athletes and gymnasts.
Having flexibility maximizes our bodies to it's fullest potential, it keeps our muscles supple, bones dense and joints mobile as we age with grace.
That, to me is the practice of yoga. It is a practice to learn about yourself, your body and you!