What is the first weird thing about the Reciever of Memory's office that is unlike the rest of the village?
Well, there are a few things. (You can find all of this in Chapter 10.)
The first thing that is strange is that the receptionist stands up to greet Jonas, but that is probably more because of who he is than because of the office.
The answer you are probably looking for is that the door was locked. No doors that Jonas knew of in the community were ever locked.
After that, the weird things have to do with the furnishings of the office. They are nicer than the ones everyone else has -- much fancier and more elegant. Finally, there are lots and lots of books.
In the book "The Giver" Jonas goes to the giver's home for the first time. He does not really understand what his assignment is going to entail, but he is curious. At the giver's home he is amazed to find that the giver has shelves of books. He looks around at all of the books. The giver is also allowed to lock his doors, but one of the other most significant things is that the giver is allowed to have true privacy. The giver turns off the speaker system and whatever the monitor system is that monitors the community is not allowed to monitor he activities during Jonas and the giver's interaction.