Welcome back to "Doggerel," where I ramble on about words and phrases that are misused, abused, or just plain meaningless.
When you don't feel like answering questions, one of the quickest ways to answer one and drop the line of inquiry is "it's complicated." If I'm watching a middle episode of Death Note, and someone steps in and asks why someone's doing something, I'd be tempted to just say, "it's complicated" and leave it at that. If I'm specifically seeking knowledge of a topic from someone who's gone through the trouble of leaving a dissenting opinion on one of my blogs, well, it's frustrating to get a brush off. It doesn't contribute to learning.
One of the more common abuses of "complex" as doggerel comes from fans of "Intelligent Design": They often assume complexity itself is a sign of design. Of course, there are plenty of instances of unnecessary complexity in life. Additionally, simplicity can be a stronger indicator of design than complexity. For example, A butter knife made from a single piece of metal is better designed than a complex array of parts that happen to have a long, flat metal surface sticking out for the purpose of spreading butter on bread.
Another difficulty is in defining complexity. Is it number of parts? Amount of DNA needed to pull it off? One alleged attempt was "Complex Specified Information," which ends up contradicting itself in its definition. Anyway, evolutionary processes can increase information quite well, and complexity with it.
Still another difficulty for ID is that if complexity can't arise without intelligence, where did the complexity of the designer come from? They usually make special exceptions in logic for this so that they don't have to explain anything.