Luck

Luck is the tendency to be affected by strange turns of fate. The target's luck is considered "good" or "bad" depending on the recent trend of outcomes, but luck is fickle, and the direction can change rapidly. (This trend is semi-random and weighted.) Random enemy encounters are more common, especially special enemies, good loot is either great or garbage, and during a "good" trend, gambling generally resolves to the player's benefit in the end -- until the streak suddenly ends.

Luck is displayed in the UI as a curse. When attempting to dispel Luck, your odds of success are based on your current trend. This makes it only practical to dispel Luck when your luck is "good". Attempting to dispel Luck, but failing, causes it to spread to the person performing the dispel like an infection. Wise NPCs will either refuse to dispel Luck due to this risk, or they will set their price for doing so exorbitantly high.

Consider this more like Mat Cauthon's "dice are rolling in your head" effect.