Gimme your lunch money!
(The room I am in right now has the same ceiling as wall.)
That being said, in MC different floors and ceilings are hard. Less hard now that we have carpets, but still.
(Single block floor / ceiling = same floor as ceiling. 2 blocks = no room for wiring. 3 blocks = absurd height per floor. Microblocks can help, but tend to be laggy due to all the tile entities. There are some tricks that can be used like alternating two blocks, but they have limited use as they require both blocks to be suitable for both floor and ceiling.)
Personally, I tend to do 2 floors and then a utility floor, which sidesteps a large chunk of the issue.
Also, returning to the original subject, yes, I tend to build boxes. Why? I'll explain.
In this game, as in all sandbox-like games, there's a balance. Efficiency versus aesthetics. I try to do aesthetics as much as possible, but only without compromising efficiency. In practice, this means that my aesthetics are limited at best.
So, why boxes? A couple of reasons. First off, they are efficient space-wise. Not an issue directly, but it reduces the time to move between machines and keeps wiring / pipe runs as short as possible, both because wiring is relatively easy and because they are easily modular. Second, they are easy to automatically build, be it with fillers, turtles, or otherwise. Third, they don't require many blocks compared to the amount of internal space, which again saves time getting resources.