Motivational speakers have been touting the benefits of positive thinking for years, but recent studies in the US and Europe have proven its value. A positive attitude can slow down onset of age-related health problems, improve immune system function, boost cardiovascular health and even improve chances of recovering from serious illness. In one study, a positive attitude was even shown to help fight the common cold.

Interestingly, it has been found that repeated use of "negative" words can undo a positive attitude and its benefits. For example, elderly people referred to as "distinguished" or "accomplished" tend to perform better in mental assessments than those primed with words such as "feeble" or "senile" before being assessed.