Actually this goes way back to catspaw's using a four letter word (Dago). My dad came over from Italy when he was 12, moved to the DC area with his family, found he was being really hassled about his accent etc. He was a tall skinny guy (He still only weighed 135 pounds when he was 27) and looked like a pushover, but he got lots and lots of practice in fighting because he would fight like a tiger if anyone called him a Dago or a Wop. Fairly soon, he was winning most of the fights.

By the time he was 18 or 20, it finally dawned on him that the only people left who were calling him Dago were his friends. They couldn't resist teasing him, because he would invariably light into whoever had said it. Once he realized what they were doing, he lightened up, and his good friends called him a Dago all his life (with no more repercussions.)