A goal is a desired result a person or a system envisions, plans and commits to achieve a personal or organizational desired end-point in some sort of assumed development. Generally speaking, a person endeavors to complete this goal within an allotted amount of time, set personally, or by an authority (teacher, boss, parent, etc.).
There are different types of goals with varying levels of importance and time allotted to complete. For example, an important goal would be attempting to complete a task in school, which if not completed, would result in the individual failing the class. While this goal would be considered a 'short-term' goal, the outcome is critical for the individual's personal success.
While not every goal is absolutely critical for an individual's personal success, consistency, to complete set goals, is crucial for building self-worth and self-confidence. If a teen allows failure of completing assigned, prearranged goals to become habitual, they may develop a mindset of low self-worth and feel as if they are a failure. Contrariwise, a teen who consistently completes goals, whether personally assigned or appointed by authority, are able to develop a self-worth of high self-esteem, further developing their self-confidence and improving their chances of future success.