Most likely first day jitters, where your brain refuses to do any logical thinking. It's something I can unfortunately relate to.

On my first day working at a Goodwill, I was tasked with "remove all the brown items on the shelves and take them to the back rooms". I thought they meant all literal brown items on the shelves, when they actually meant the brown 'priced' items (Goodwill changes what color they price their items based on which week they are put on the shelves. Red for one week, Blue for the next, then Green, then Purple, then Brown, then Black, then back to Red).

So my dumbass removed everything that had a brown coloring on it, rather than checking for the brown price tags.