Each one is a service that passes its tests and still fails in production. Pick one.
A one-minute outage turned into twenty. The visible tests pass. Work out what production does that the tests do not.
A product page calls inventory at most 3 times, however it fails.
Retries wait before trying again, and wait longer each time.
Pages that fail at the same moment must not retry at the same moments.
Once inventory is back, the shop recovers instead of keeping it overloaded.
A brief failure is still retried. A product that does not exist is never retried.