1. A gaming system comprising: at least one processor; at least one display device; at least one input device; and at least one memory device storing a plurality of instructions which, when executed by the at least one processor, cause the at least one processor to operate with the at least one display device and the at least one input device to: (a) determine first estimated emotional state data for a player, the player's first estimated emotional state data representing a first estimated emotional state of the player; (b) determine whether at least one of one or more designated events occurs in association with one or more plays of at least one of a primary game and a secondary game, each of the one or more designated events being associated with one of a plurality of expected emotional reactions; (c) for each of the one or more designated events, for each occurrence of said designated event, modify the player's estimated emotional state data using expected emotional reaction data representing the expected emotional reaction associated with said designated event such that the player's modified estimated emotional state data represents a current estimated emotional state of the player; (d) determine whether one of one or more triggering conditions associated with the player's current estimated emotional state is satisfied; and (e) if one of the triggering conditions is satisfied, modify an aspect of at least one of the primary game and the secondary game and display said modified aspect.