Rosy retrospection

Rosy retrospection refers to the finding that subjects later rate past events more positively than they had actually rated them when the event occurred, reminiscent of the Latin phrase memoria praeteritorum bonorum ("We remember the good things of the past")

The effect appears to be stronger with moderately pleasant events and is usually explained as a result of minor annoyances and dislikes "fading" from memory dramatically faster than positive situations.

Experiments
In one group of experiments, three groups going on different vacations were interviewed before, during and after their journeys. Most followed the pattern of initial anticipation, followed by mild disappointment. Generally, most subjects some time later reviewed the events more favorably than they actually did while experiencing them.