People routinely report that waiting for a difficult event was worse than the event. That is not a distortion of memory, and the reason lies in what the anticipatory period does and does not allow.
Anticipation triggers the same response
The stress response is initiated by appraisal rather than by the event itself, so imagining a demanding situation engages much the same physiology as encountering one.
Heart rate, muscle tension and attentional narrowing all appear before anything has happened, which is what makes rehearsal so convincing.
Since the appraisal can be repeated indefinitely, the response can be triggered many times before the single occasion that actually occurs.
Waiting offers no route to resolution
During the event there is something to do, and action allows the response to run its course and subside.
Waiting supplies no action, so the physiological activation persists without the behaviour that would ordinarily complete it.
Which is why people often describe a paradoxical relief at the start of a difficult meeting or procedure, since the arrival converts an open state into a closed one.
Uncertainty carries its own cost
Studies of anticipated discomfort find that not knowing whether something will happen is frequently rated as harder than knowing it will.
An uncertain outcome cannot be prepared for in one direction, so the mind maintains readiness across several possible futures at once.
This is the mechanism behind waiting for test results or a decision, where the actual news, whichever way it falls, is often followed by a drop in tension rather than a rise.
Rehearsal has a useful version and a useless one
Preparing for a specific scenario, working through what would be said and what would follow, converts an unbounded worry into a plan and generally reduces the load.
Repeating the same catastrophic image without adding detail or reaching an action changes nothing and reinforces the appraisal that generated it.
The distinguishing question is whether the rehearsal is producing new information, since worry that is doing work ends and worry that is not simply loops.
Why shortening the wait helps disproportionately
Organisations that reduce waiting times for decisions and results are addressing a real load, not merely an inconvenience.
The same logic applies personally: a difficult conversation scheduled for next week is paid for daily until then, while one held tomorrow is not.
Where the wait cannot be shortened, structuring the period with defined activity is the usual approach, since the anticipatory state occupies whatever attention is left unallocated.