The sad thing was that as much as Edmund would absolutely have loved to give Eustace the thrashing of a lifetime for his unseemly conduct he could understand exactly why the younger boy was acting the way he was. And not just because Edmund remembered his own less than exemplarily conduct on his first trip to Narnia. For Eustace who had been raised in a world of embassies and republics and vegetarianism, Narnia was a culture shock. The idea of a wooden sailing ship with a mast and oars was almost certainly completely alien to the young boy who had posters displaying the inner workings of huge cruise-liners on his walls, the idea of Kings and Queens who had ultimate authority to a child who could explain (probably better than many adults) the inner workings of and supported a 'parliamentary democracy' was undoubtedly absurd. Eustace who had never even read stories about dragons, could almost be forgiven for being foolish enough to allow himself to be turned into one and could only be commended for breaking Caspian's spare sword fighting a sea monster.
Narnia was more than just another world to Eustace; it was an entirely different sort of existence.