Positive Psychology

Each of us has an invisible bucket. It is constantly emptied or filled, depending on what others say or do to us. When our bucket is full, we feel great. When it's empty, we feel awful.
Each of us also has an invisible dipper. When we use that dipper to fill other people's bucket - by saying or doing things to increase their positive emotions - we also fill our own bucket. But when we use that dipper to dip from others' buckets - by saying or doing things that decrease their positive emotions - we diminish ourselves.
So we face a choice every moment of every day: We can fill one another's buckets, or we can dip from them. It's an important choice - one that profoundly influences our relationships, productivity, health, and happiness.

From How Full is Your Bucket?