At the same time, this principle must be supplemented by another consideration.

Suppose that I am very desirous that time should not pass quickly.

If, for example, I am enjoying myself or indulging in idleness, and know that I have to be off to keep a not very agreeable engagement in a quarter of an hour, time will seem to pass too rapidly; and this not because my thoughts are diverted from the fact of its transition, for, on the contrary, they are reverting to it more than they usually do, but because my wish to lengthen the interval leads me to represent the unwelcome moment as further off than it actually is, in other words, to construct an ideal representation of the period in contrast with which the real duration looks miserably short.
Our estimate of duration, when it is over, depends less on this circumstance of having attended to its transition than on other considerations.

Wundt, indeed, seems to think that the feeling accompanying the actual flow of time has no effect on the surviving subjective appreciation; but this must surely be an error, since our mental image of any period is determined by the character of its contents.

Wundt says that when once a tedious waiting is over, it looks short because we instantly forget the feeling of tedium.