jackie ward witnessed the family of four have racial slur shouted at them while they were out for the day on friday .
shay stewart-bouley , who is black and runs a blog called black girl in maine , was with her white husband and their daughter , 9 , and son , 23 .
car of unidentified white males drove past as one shouted ` hey n ***** s ! '
ward said she shared the story to remind people to be kinder to each other .