The mood of your star is important in determining the rate of success at appearances.
At 0 mood points, the star is unhappy and has a -20% success rate.
At 500 mood points (the maximum), the star is happy and has a +20% success rate at appearances.
Mood can be raised by going on dates, certain events and from purchases from the Gift Shop. The mood gained from dates when current mood is low is generally greater than that of a high mood.
Mood decreases over time at a constant rate.