If I remember correctly, they celebrated birthdays at one time too.

My (mom's side) great grandmother and grandmother were both life long witnesses, but somehow always made me a cake on my birthday, despite the ban.. they even gave presents ( this in the late 1960's, early 70's). I remember it quite clearly. My Dad was scandalized at this , and it was a source of conflict between the families ( Dad's family were later converts) Around 1972 the practice stopped for good, and there was no mention ever made of birthdays after that... except for discussions about John the Baptist's head on a platter.