What do you think this "lost" means? "waste something"?
30)After teaching first grade for a couple of years, I switched to second grade. I would have the same classroom and a number of the same children, so I decided to make the room “new” for returning pupils. I rearranged furniture, added new pictures and visual aids, and moved flowerpots to new areas. I wanted my children to be surprised at the new environment. My efforts were lost on one student, though, whose mother told me the child said everything was exactly the same. “But,” she added, “she really likes the color of your new eye shadow.” At that very moment, what she said to me struck me dumb.
***** NOT A TEACHER *****
One of their students didn't notice that they rearranged the furniture. In other words, their efforts didn't pay off.