The Difference Between 2D and 3D

The episode of The Simpsons, I think was a Halloween special where Homer goes from 2D to 3D. And he's totally amazed by everything and I'm sure it would be equally amazing for us to go to 4D. There's just real questions, scientific questions when you talk about different dimensions,. Like, how does the relationship between surface area to volume change in another dimension? Could you actually fit more inside something than there is of that object?