What's the single best rule to follow in programming?

Actually, I think there are 2 that are equally important; one that pertains to code construction, the other to design (and so it may be the single most important thing). I've recently seen these both expressed in a new light.

The frst (pertaining more to construction than the other) is brevity or code less. The first link, especially, sheds light on just how important this rule is.

The second, one which I'm going to rate as the best rule simply because it always pertains to architecture and as such should have a greater effect on the system under development, is reduce complexity.

The linked interview with software luminary Roger Sessions is the best I've heard in quite awhile. In the interview, Sessions proposes using "equivalence relations" to determine the best possible partitions in developing enterprise architecture.

You can listen to the interview for a further explanation, but I think his best points were about complexity. He demonstrates (by contrasting the huge reduction in potential states representable by a single program with 12 variables [and 6 states] to 2 programs with 6 variables each) that partitioning a system greatly reduces complexity.

Outwardly partitioned programs may not really be, however. If 2 "separate" programs (like services or whatever) share a database, they're not partitioned.

Sessions proclaims OO as the "worst partitioning technology". Now, I've read a fair amount lately in favor of FP over OO, and the arguments are pretty good. But I don't think they came close to Sessions' position against the traditional OO model - the creation of large hierarchies which merely tie everything together. He's not opposed to OO, mind you, just the typical implementation where reuse is a major goal.

"Reuse at the expense of complexity is unacceptable. Reducing complexity is much more important than reusing code; it is the most important thing."

The interview was so interesting to me that, for a moment, I felt excited about things like architecture. Then I remembered that I'm code wannabe and that I work at BloatedCorp (on the Behemoth project) and I snapped back to reality.