At my workplace, there's a bulletin board where people have put up Christmas cards and pictures of their children or pets. In the latter case, there are several pictures of dogs of various sizes, often wearing sweaters or fake reindeer antlers.
I was looking at those pictures, and noticed that there weren't any pictures of cats dressed up like that. I wasn't surprised. Dogs are long-suffering and will put up with a lot of stuff, and just look at you reproachfully as you take the picture of them wearing the fake antlers. Cats, on the other hand, ain't playin' that game. The average cat's reaction would be, "You put that on my head and I will claw bloody furrows into your arm." Believe it. If you want an elf hat on your cat, you'd better Photoshop it in.