7 thoughts that Are Bad For You : Our personalities do more for us than determine our social circles. Temperament can impact a person’s physical health. “The idea that behavior or personality traits can influence health is one that’s been around for a long time. We’re just now getting a handle on to what extent they do,” said Stephen Boyle of Duke University Medical Center in North Carolina. From those with a chill demeanor to the completely frazzled types, mental factors are ultimately tied