To keep a promise

1. You won't be worried about it.
2. It will be easier to decide between things.
3. Others will accept your help in the future.
4. People will be more likely to ask for your help with difficult things.
5. You'll help bring happiness to others and yourself.
6. You will be able to gain someone's trust or strengthen their trust in you.
7. Another's burden could be lightened.
8. Friendships could be made.
9. You'll be able to sleep easily.
10. It will show that you understand the important of the promise, regardless of whether it is a large or small one.