Most developers are morons, and the rest are assholes. I have at
various times counted myself in both groups, so I can say this with
the utmost confidence.
# Assholes
Assholes read specs with a fine-toothed comb, looking for loopholes,
oversights, or simple typos. Then they write code that is meticulously
spec-compliant, but useless. If someone yells at them for writing
useless software, they smugly point to the sentence in the spec that
clearly spells out how their horribly broken software is technically
correct, and then they crow about it on their blogs.
There is a faction of assholes that write test cases. These people are
good to have around while writing a spec, because they can
occasionally be managed into channeling their infinite time and energy
into finding loopholes before the spec is final. Unfortunately,
managing assholes is even harder and more time-consuming than it
sounds. This is why writing good specs takes so long: most of the time
is frittered away on asshole management.
# Morons
Morons, on the other hand, don't read specs until someone yells at
them. Instead, they take a few examples that they find "in the wild"
and write code that seems to work based on their limited sample. Soon
after they ship, they inevitably get yelled at because their product
is nowhere near conforming to the part of the spec that someone else
happens to be using. Someone points them to the sentence in the spec
that clearly spells out how horribly broken their software is, and
they fix it.
Besides the run-of-the-mill morons, there are two factions of morons
that are worth special mention. The first work from examples, and ship
code, and get yelled at, just like all the other morons. But then when
they finally bother to read the spec, they magically turn into
assholes and argue that the spec is ambiguous, or misleading in some
way, or ignoreable because nobody else implements it, or simply
wrong. These people are called sociopaths. They will never write
conformant code regardless of how good the spec is, so they can safely
be ignored.
The second faction of morons work from examples, ship code, and get
yelled at. But when they get around to reading the spec, they
magically turn into advocates and write up tutorials on what they
learned from their mistakes. These people are called
experts. Virtually every useful tutorial in the world was written by a
moron-turned-expert.
# Angels
Some people would argue that not all developers are morons or
assholes, but they are mistaken. For example, some people posit the
existence of what I will call the "angel" developer. "Angels" read
specs closely, write code, and then thoroughly test it against the
accompanying test suite before shipping their product. Angels do not
actually exist, but they are a useful fiction to make spec writers to
feel better about themselves.
# Why specs matter
If your spec isn't good enough, morons have no chance of ever getting
things right. For everyone who complains that their software is
broken, there will be two assholes who claim that it's not. The spec,
whose primary purpose is to arbitrate disputes between morons and
assholes, will fail to resolve anything, and the arguments will
smolder for years.
If your spec is good enough, morons have a fighting chance of getting
things right the second time around, without being besieged by
assholes. Meanwhile, the assholes who have nothing better to do than
look for loopholes won't find any, and they'll eventually get bored
and wander off in search of someone else to harass.
