I am a receptionist so I am not allowed too have many personal effects on my desk. While this does annoy me to a certain extent, I realize that my employer is very nice to allow me to wear what I want (within reason) AND I can listen to my music. I also think they are nice to allow me to have some personal things on my desk at all. I think this is more than a fair trade. I do have 2 pictures of my son, my Hello Kitty mug, my tea pot on my desk.
On Halloween, one of my coworkers gave me some pumpkin candles that are very small. I do put those on my desk because they are subtle. I don't think I can decorate for Holidays either, I never really bothered asking. The way I see it, the front entrance is gorgeous, well maintained, and is very professional looking. I think by having decorations would only be a distraction from that and we want our clients to focus on our brands, not Holiday décor. The last pic is my key chain. I am really bad at losing keys so if anyone finds them, they will automatically know that they belong to me!