If you’re one of those people who like to make to-do lists on a regular basis, then listen closely: When you’re setting your goals, it’s better to be specific and set goals you know you can achieve. For example, instead of setting a goal like "save the environment," try to recycle more.

Those two examples were tested on a group of 127 volunteers in a study published last year. The first group were provided a series of specific goals like “increase recycling,” while the second group had broader goals like “save the environment." Even though the second group completed the same tasks as the first group, the people in the second group reported feeling less satisfied with themselves than the first group. The people in the second group also reported a lower overall sense of personal happiness from completing their goal, the scientists report.