people with low levels of stress live longer and have less chance of heart attack(lower blood pressure) than people who stress a lot. people who avoid making enemies have less stress because people who make enemies tend to devote attention to those type of scenarios(and encountering their enemies). this not only causes confrontations, but creates stress in the persons free time, which, if you go further, offsets a persons "baseline" mood, making them even more prone to making more enemies by being high strung/short tempered. simply, it's a snowballing effect.
there are many more factors, scientific as well as simply logical. but in short, yes.