At school, we usually looked at what people's middle names were - one of my friends had the middle name Irvin. In 6th form we found out that the teacher who was Head of 6th form had the middle name Dudley, and in the 6th form we had a bit more leeway with what we could and couldn't say to teachers outside of lessons. Luckily for him, it was 6 years after my year left school that the first Harry Potter book was published. I couldn't take part in any of the comments as he was also Head of my house and most of the times I saw him was in House meetings or at House events and as House captain I couldn't make any comments in front of the younger pupils.