Having an agreeable personality might make you popular at work and lucky in love. It may also enhance your brain’s built-in painkilling powers, boosting the placebo effect.

Researchers at the University of Michigan, the University of North Carolina and the University of Maryland administered standard personality tests to 50 healthy volunteers, identifying general traits such as resiliency, straightforwardness, altruism and hostility. Each volunteer then received a painful injection, followed by a placebo—a sham painkiller. The volunteers who were resilient, straightforward or altruistic experienced a greater reduction in pain from the placebo compared with volunteers who had a so-called angry hostility personality trait.

http://www.scientificamerican.com/article.cfm?id=placebos-work-better-for-nice-peopl