I used to work for an ambulance company and my female partner had just dyed her hair from red to brown. One of our patients was a totally blind man that we transported regularly from his home to the hospital for treatments, who knew us all by our voices. Well, it was my turn to drive that day and I heard him say to my partner that he didn't recognize her. Her response to this BLIND man was "Oh, well that's because I used to be a REDHEAD!" She realized too late what she had said but it was too late. After hearing nothing but complete silence in the back of the ambulance for about 20 seconds I just couldn't take it anymore and busted out laughing!