What breaks first under load?
Queues, retries and capacity, simulated before the incident, not after.
The question
Requests arrive at random and one worker serves them. Near full load the queue stops being polite. Move the load and see the tail grow.
What the model assumes
One worker, random arrivals, no retries, example rates.
Results are hypotheses, not facts. Example models use round example numbers, not measured data. See honesty rules.