The glass was not in the way. The cat moved it anyway, watched it fall, and looked at you as if the experiment had been a success. She is not trying to ruin the table. She is doing what a hunter's paws are for: testing whether a thing moves, and then whether you do.
Most of this is normal. Some of it is boredom with a receipt. Almost none of it is fixed by telling her off after the crash, which she will file under "the crash works."

