Let's go back that very first illustration of the house, the one where we see it from the outside. It looks remarkably like the big, red FUN-IN-A-BOX that houses Thing One and Thing Two (147-151), don't you think?
Just like he opens the box o' fun, the Cat manages to transform what looks like an ordinary house into FUN-IN-A-BOX, housing two potential future wild Things—Sally and bro.
What do you think of Thing One and Thing Two's living situation? Should they or shouldn't they be kept in a box? Does being kept in a box contribute to their chaotic behavior, or are they just so naturally chaotic that they need to be kept in a box? Is there really any difference between the red box the Things are kept in, and the red box the kids are kept in?