Arguing is (almost) never fun.

Whether you're fighting with your significant other, friends, coworkers, or family, a bad fight can leave you feeling unhappy and overwhelmed for days on end.

More often than not, it also keeps you from achieving the very goals you're arguing about.

A study of nurses found that when they argued about patient care on the treatment floor, they were less likely to arrive at a good decision, and lost focus on the task at hand in favor of interpersonal conflict.

But we don't always have a good sense of why we fight. What pushes us to the point of conflict, when we know it will make us unhappy? And why does it leave us feeling so glum afterward? These findings from the world of psychology offer some less-than-obvious answers.