Assignation of emotional states to computer-implemented entities

Described herein are various technologies pertaining to assigning an emotional state to a computer-implemented entity. The emotional state is a function of data values in a data stream output by a data source, such as a sensor or a web service. The data values in the data stream are processed over time to generate a measure value. Values that are indicative of a dynamic state of a measure relative to an optimal measure state are computed and assigned to the measure based upon the measure value. A reaction of the computer-implemented entity is determined based upon these values. A customized personality for the computer-implemented entity maps reactions to respective emotional states, and an emotional state that is mapped to the reaction is assigned to the computer-implemented entity.