A system can be safe in normal conditions while normal conditions are the least important part of its job.

A system that works in normal conditions has not yet been tested, because normal is not what it exists for. The whole value of a safeguard sits in the rare hours when things go wrong, and performance during the easy stretch tells you almost nothing about that. Reliability under ordinary load is the least informative evidence available.

This is worth applying to your own arrangements. A budget that works in a good month, a routine that holds when you are well, a relationship that is easy when nobody is under pressure: none of these have been examined. Ask how each behaves under strain, and where possible test it deliberately rather than waiting for the strain to arrive.