Researchers have found that people who have antagonistic or disagreeable personalities are more prone to strokes and heart attacks. In a study of more than 5,000 people in Italy, scientists found that people who ranked in the lowest 10 percent of agreeableness were 1.4 times more likely to have thickening in the lining of their carotid artery than people who scored higher on scales for agreeableness. Investigators say that this finding held true even when they factored in people's smoking...