I have never received coal, but I have gifted it :-). My boss's son for three years straight didn't even get me a card for the holiday so one year I decided to mess with him and wrapped a piece of coal in a nice box and handed it to him. I knew he would open it right away and the look on his face was absolutely priceless! His mother (who I also worked with) thought it was hysterical and vowed to gag gift it to someone else that year. I did eventually that day give him a real present.