Whats the big deal?
Definition of flexibility:
Muscles and joints working together to move in a full range of motion.
You could get injured with out it.
If you do any physical activity without stretching before hand, you could get seriously injured. Even doing a small thing like standing up could hurt.
How to improve flexibility:
1) Stretch everyday. When you wake up, before you go to bed, and before any physical activity.
2) Try dance, gymnastics, pilates, or yoga. They help engage muscles to improve flexibility.
3) Drink lots of water. Water keeps your muscles healthy and strong. It is always good to stay hydrated.