the person in war joins a group or gets new friends they might be a different personality then that person so the more they hang out the more they change.Or the person that is left at home might do new activities that might change their personality too.Or maybe either of them might do something that one of them doesn't like and those can end up in negative effects like lose of love or seperation.But if someone was acting wrong before, now that they miss that person they might try to do something right so that they could see each other earlier than normal.that would end up as a positive effect.