My Child is the "Mean Kid"

My child is the mean kid at daycare, crap, how did this happen? Dan picked up Katelynn from daycare yesterday and was told that Katelynn made the other little girl cry. Katelynn apparently told the other little girl that she was "ugly" and then followed up with "and you have ridiculously ugly hair". The other little girl had her feelings hurt and cried and Katelynn could have cared less. How did this happen and where did it come from? Yes, I'm sure many of you are thinking - "hello, you are not the nicest person and would probably do something like that" - true in fact, but that is not what I have taught my child. So last night after voting we had a talk about being nice and having friends and not being nice and having no friends and how disappointed her Grandparents would be in her for making another kid cry. She had strict instructions from her daddy to apologize and hug the other little girl today at daycare, I am hoping that she follows through with this. Mom - was I the mean child when I was little? (I have a feeling I already know the answer to that question, but really at 3 years old?) I guess on one positive note - at least my 3 year old has a really good vocabulary - what other 3 year old says "ridiculously"?