The Chalice of Regret

In the Keep of House Kerberoth, in the Lands of Chaos of the plane of Tanuel, there is a cabinet. A chalice is kept in this cabinet. It is called the Chalice of Regret.
Those who drink from the chalice suffer regret. The regretful become hesitant (penalties to initiative value) and indecisive. The consequences of their actions prey on their minds and left to their own devices, they will eventually become unhinged.
If, however, Sweet Regret is added to the chalice, then the following benefit applies to the next person to drink from it:
They may revisit one decision that they made in the past, and choose another path. It may be that the new path chosen by the imbiber is not accepted by the chalice, in which case nothing happens. If, however, the new path is acceptable, then the drinker's past is re-written to accomodate the change.
Whatever the resolution, the imbiber is not afflicted by the negative effects of the chalice.
An intelligent adventurer might consider preparing the projected consequences of such a change ahead of time to moderate the chalice's reputation for capriciousness. The more modest the projection, the greater the chance of acceptance.