There is one type of illness in the world that affects more people than anything else and is very deadly. If untreated this illness could affect everything you do. What is this illness? Depression. Serious depression requires professional treatment. Self-induced depression is something each of us can change. Everyone's circumstances are different, but the causes of self-induced depression are common: low self-esteem, hurtful thinking and a bad attitude. So how can we change the way we think, feel, and cultivate a cheerful attitude? First we must look at ourselves, truly and honestly examining our motives for what we wish to achieve. If you are dissatisfied because you feel you haven't or can't do anything, then one step is needed - to set goals. Always start your goals relatively small and easy to attain. Think of them as sand; one grain may be insignificant but as a group they form the beach. Once you have set and attained small goals for yourself, move on to slightly larger, more challenging goals. It takes more than just setting goals to be happy. It takes positive thinking. How can we attain this? There are a number of factors that can make us think negatively and one of those is diet. In my opinion, a person who eats a lot of take out and fast food is feeding their body junk. Start by eating better foods which give the body much NEEDED minerals. If your physical body is happy, it's much easier for your mental body or "thinking ability" to be happy. Next, exercise. A half-hour a day is recommended for positive well being. Then think about good memories you had, or generally think of things that make you smile. Remember, everything you wear costs money but to wear a smile is free. A smile can be the difference between an average day and a great day. If you follow these steps, positive change is inevitable. According to the passage we can learn that   _  .
a practical goal can help people to achieve a sense of success we shouldn't be satisfied with small goals that are insignificant we should avoid challenging goals that may lead to failure people can enjoy happiness only if they set reasonable goals