You would excepct that it is the day after your birthday the surgeon is worse (risk for hangover or less sleep).
I personally was under the impression that once you left childhood and the impatience of getting presents your birthday pretty much became just a day as usual. That also seems to be how my college treats it but it might be cultural. Europe is not a homogeneous place.
Well, if you're lucky, your co-workers will chip in and buy a cake!
They might pitch in and buy you a small present, in return.
But they definitely expect you to bring a cake or at least some sweets.
People often bring cake to work on birthdays, though.
Then again, I grew up having my birthday in the "herfstvakantie" and the habit kind of stuck :-)