7. A computing device, comprising: a processor configured with processor-executable instructions to perform operations comprising: monitoring activities of a software application operating on the computing device to generate user-persona information that characterizes a user of the computing device, the generated user-persona information including information that characterizes the user's mood; using the generated user-persona information to select two or more device features; monitoring the selected two or more device features to collect behavior information; determining whether the user's mood is relevant to analyzing the behavior information collected by monitoring the selected two or more device features; and generating a classifier model that includes a plurality of one-level decision trees that each evaluate a device feature in relation to the user's mood in response to determining that the user's mood is relevant to analyzing the behavior information collected by monitoring the selected two or more device features; generating a behavior vector that correlates the behavior information for which the user's mood is relevant to the user's mood at the time the behavior information was collected; applying the generated behavior vector to the classifier model to generate an analysis result; and using the generated analysis result to determine whether a device behavior is non-benign.
9. The computing device of claim 7 , wherein the processor is configured with processor-executable instructions to perform operations such that using the generated user-persona information to select the two or more device features comprises: selecting the two or more device features that are most relevant to determining whether the device behavior is not consistent with a pattern of ordinary usage of the computing device by the user.