Judgement and reasoning traps

you stopped comparing frameworks and worked out what the system actually has to do, in numbers.

First principles

the graph turned at 14:07 and someone asked what shipped at 14:05.

Null hypothesis of an outage

latency and CPU rose together and you spent two hours on the CPU, which was a symptom of the same queue.

Correlation is not causation

you believed it was the cache and read the logs looking for the cache, and found something.

Confirmation bias

reading the timeline afterwards, the cause was obvious, and at 02:00 it had not been obvious to anyone.

Hindsight bias

you copied the architecture of a company that succeeded, and never saw the twenty that did the same and folded.

Survivorship bias

someone said two weeks before anyone had estimated, and every number afterwards was near two weeks.

Anchoring

the migration has taken eight months, so the argument for continuing was that it has taken eight months.

Sunk cost fallacy

the decision has been in review for six weeks, and the options have not changed since week two.

Analysis paralysis

the design covered what happens when it works and the review found nothing about what happens when the vendor is down.

Happy path thinking

someone asked how to parse a filename with a regex, and what they actually needed was the file's creation date.

XY problem

you explained the bug out loud to a colleague and worked out the answer before they said anything.

Rubber duck debugging

the team adopted the whole process from a conference talk without the constraints that made it work there.

Cargo cult

the team wrote its own scheduler because the existing one did not fit exactly, and now maintains a scheduler.

Not invented here

the new technology was chosen before the requirements were written, by the person who wanted to learn it.

Resume-driven development

the build took forty seconds two years ago and takes eleven minutes now, and nobody remembers a day it got slower.

Boiling frog