Weird stares, especially those that come while you cross the street or walk through a mall while making chicken sounds.
Right,
Nilp?
Professors who continually enjoy their holiday breaks when school is supposed to resume on January 2.
Friends you've known for merely months who ambush you the day before your birthday. I was busy celebrating a friend's birthday a while ago (after partly successfully surprising her) when another came up to me and asked me to accompany her somewhere. I ended up being surprised myself as well, although it was rather advanced, but I have no problem with that.
And no classes on the day of your birthday. It protects you from further surprises.