People are often feel obligated to set goals in order to define achievement. Without specific goals, defining achievement can be rather difficult. With goals in place, we can tell when we have achieved success.
Finding a sense of success in life has emotional, professional, social and psychological ramifications. Simply put, we feel better about ourselves when we feel we have accomplished something. This is true in a small-scale way and in a larger, life-context way.
There is intrinsic value to accomplishment as well as extrinsic value. When we prove to ourselves that we have achieved something, we feel potent and capable. There is also a sense that we have spent our time doing something worthwhile, even if the goal we have accomplished is relatively small or easy.
Reaching a goal adds value to our lives.
From the outside, a person's accomplishments lend value as well, creating a persona, a resume, and/or a reputation of accomplishment. Even in small ways, this social effect of accomplishment can help us move through life with an inward and outward sense of power and worth.