Dave's Birthday?

I surprised Dave at his office for his birthday. I brought him our belated Christmas present and he showed me around his office. I saw the library, his future office and Lynne's office (shown). He tried to be polite but after I asked him what he had planned for the evening, he had to admit to me that his birthday was the 6th, not the 5th. I had arrived a day early. Nice thought, poor execution.