|I really enjoyed this, and I don't say that often. However, it is possible to over-describe your scenes, which I feel you were doing here.
"The joke fell flat somewhere between my brain and reality. No matter what I tried, the mannequin continued to stare at me with her unnerving cobalt eyes. All the stupid-skinny-frozen-people were. Somewhere in the deep recesses of whatever logic I still possessed, I knew the thought border-lined complete whacko. Mannequins didn’t actually stare. They were inanimate objects. Right?"
I loved this, but the description was just too much. You used both "unnerving" and "cobalt" to describe her eyes. One descriptive word could have sufficed. Also, "recesses", "logic", and "possessed" were a bit much, as well.
You are talented. Keep it up.