Final answer:
Each sentence was examined for errors; the first and third are correct, the second has redundancy, and the last is also correct, providing a personal example regarding saving enough money.
Step-by-step explanation:
Identifying the type of error in the given sentences involves examining each one for issues in grammar, punctuation, coherence, and proper sentence structure. The sentence 'Having goals can also help people feel a sense of accomplishment' is correct as written. This initial sentence effectively sets the context for discussing the value of setting and achieving goals.
The sentence 'If you set attainable goals and work to achieve them, achieving goals you have set for yourself makes you feel proud, and it motivates you' could be seen as redundant due to the repetition of the concept of achieving goals. A clearer version might instead focus on the feeling of pride and motivation that comes from setting and then reaching those goals, without repeating 'achieving goals'.
The sentence 'It also can help you overcome challenges in your life now or in your future' is also correct as it illustrates the broader benefits of goal setting.
Last, the sentence 'For instance, when I realized that I had saved enough money to buy the skateboard I wanted, I felt proud of myself' effectively uses a personal anecdote to emphasize the sense of accomplishment one can feel when achieving a financial goal. The narrative resonates with setting SMART goals and the emotional payoff from realizing them. This sentence is correct as well.