This article walks through one afternoon of Debian system management, in which the machine turned out to have been reporting two of its own defects continuously, for as long as it had been configured, to nobody.
Debian tells you almost everything. It just does not tell you on screen. The kernel ring buffer, the systemd journal, systemd-analyze, dpkg, apt-cache policy and /sys between them describe the state of the machine in far more detail than any settings panel — and a desktop can look completely correct while those sources are recording a failure a few hundred times a minute.
What that gap creates is a feedback loop with a missing half. The machine emits the evidence; nothing reads it. The two defects below had both been present since the day the setup script was written, both were sitting in plain text in the journal, and neither was discoverable from the desktop:
The GTK theme was discarded at parse time, 161 rules per application launch,
2,093 log lines in the boot I measured, while reporting success and looking
