Systems Never Behave As Intended

This article will be published on 2025-11-26.

Most systems do not behave according to their design documentation, their architecture diagrams or the expectations expressed during discussions.
They behave according to the sum of their runtime conditions — conditions that are rarely fully visible, rarely fully controlled, and often only understood after something goes wrong.

This gap between intended behaviour and actual behaviour is one of the core reasons why modern systems surprise their operators, drift over time and resist prediction.

This article explains where real behaviour comes from and why the intended architecture almost never matches reality.