Complexity can signify a complex problem on a simple domain, or a simple problem in a complex domain. You simplify one place, you're just pushing the complexity somewhere else.
I optimistically called this Chester's First Law of Complexity:
Essential complexity in the problem domain is a conserved quantity.
The idea being that someone, somewhere, always has to pay the piper for any given architecture. It might be paid at write time, or at read time. By the server or by the client. By the programmer or the sysadmin. By the compiler guy or the programmer. By the code that defines the data structure or the code that relies on the data structure. But somebody always pays the toll.
Then I found out that Larry Wall had beaten me to it with the pithier much pithier "Waterbed Theory". Kolmogorov partly so with the somewhat less pithy Kolmogorov Complexity.
