My first thought "What the heck did he/she do that for?" I'd probably eventually want to watch more of the nonverbals of the person to find out if something was bothering them, but I sure would not have the first thought be anything about my worthlessness or worthiness. The dropping of the paper was that person's choice, having nothing to do with me.
I think the hardest thing for abused people to overcome, is realizing that what others do, has NOTHING necessarily to do with them...another person's actions are separate from you, meaning you did not cause them, provoke them, encourage them. That person just wanted to drop the paper on the floor, so they did. PERIOD. It most likely has NOTHING to do with you or anyone in that room, unless we are given further data proving that someone or something somehow provoked it.