So you know you should stretch, but you still don't. In an effort to turn you to the other side, here are ten more reasons to stretch [1]:

1. Decreases muscle stiffness and increases range of motion. Stretching helps improve your range of motion which may also slow the degeneration of the joints.
2. May reduce your risk of injury. A flexible muscle is less likely to become injured from a slightly extensive movement. By increasing the range of motion in a particular joint through stretching, you may decrease the resistance on your muscles during various activities.
3. Helps relieve post-exercise aches and pains. After a hard workout, stretching the muscles will keep them loose and lessen a shortening and tightening effect that can lead to post-workout aches and pains.
4. Improves posture. Stretching the muscles of the lower back, shoulders and chest will help keep your back in better alignment and improve your posture.
5. Helps reduce or manage stress. Well stretched muscles hold less tension and therefore, leave you feeling less stressed.
6. Reduces muscular tension and enhances muscular relaxation. Stretching allows the muscles to relax. Habitually tense muscles tend to cut off their own circulation resulting in a lack of oxygen and essential nutrients.
7. Improves mechanical efficiency and overall functional performance. Since a flexible joint requires less energy to move through a wider range of motion, a flexible body improves overall performance by creating more energy-efficient movements.
8. Prepares the body for the stress of exercise. Stretching prior to exercise allows the muscles to loosen up and become resistant to the impact they are about to undergo.
9. Promotes circulation. Stretching increases blood supply to the muscles and joints which allow for greater nutrient transportation and improves the circulation of blood through the entire body.
10. Decreases the risk of low-back pain. Flexibility in the hamstrings, hip flexors and muscles attached to the pelvis relieves stress on the lumbar spine which in turn reduces the risk of low-back pain.

Source [2]