Birthday surprise

The staff at work was very thoughtful and posted a sign on my locker that said "happy birthday" with the date on it.  I usually go to my locker on my breaks but haven't been able to go on a break for serveral weeks so I was unaware of this sign.

I showed up to work the last week and one of my co workers started shaking me while yelling "5 more hours!!".... I was so confused. I told him to stop shaking me and I do not know what will happen in 5 hours.  

The sign apparently indicated that it was my bday... Did I forget to mention that the sign was wrong?  It definitely was not my birthday.

Then all the other comments from everyone else started making sense

M: I won't be here tomorrow, but hope you have a great night!!

Me (thinking): What a weird but nice thing to say