Why not? would be one way to answer this question. Here are 3 more good reasons:
1. On a personal level, most people want to be able to do things well and feel good about themselves afterwards. When you feel good about yourself and what you do somehow you tend to perform even better thus reinforcing the cycle. So, it’s good for your health!
2. You get more done. When you focus on things that are important to you, your motivation grows and your energy increases. High levels of motivation and increased energy lead to even better performances and better results.
3. On an organisational level, high performing individuals and teams are the lifeblood of innovation, growth and success.
What other reasons can you think of?