When the cat gets his teeth stuck in a rice cake, we see that eventually O-san has to help him:
O-san looks at the mistress as if to say, “Why not make him go on dancing?” The mistress would gladly see my minuet continued, but, since she would not go so far as wanting me to dance myself to death, says nothing. My master turned somewhat sharply to the servant and ordered, “Hurry it up, if you don’t help quickly the cat will be dead.” O-san, with a vacant look on her face, as though she had been roughly wakened from some peculiarly delicious dream, took a firm grip on the rice-cake and yanked it out of my mouth. I am not quite as feeble-fanged as Coldmoon, but I really did think my entire front toothwork was about to break off. The pain was indescribable. The teeth embedded in the rice-cake are being pitilessly wrenched. You can’t imagine what it was like. It was then that the fourth enlightenment burst upon me: that all comfort is achieved through hardship. When at last I came to myself and looked around at a world restored to normality, all the members of the household had disappeared into the inner room.
I Am a Cat, chapter 2 (emphasis mine)
Why does O-san have a 'vacant look on her face, as though she had been roughly wakened from some peculiarly delicious dream'? What does this imply?