The document summarizes 3 experiments that investigated the effect of repeated exposure on pleasurable human-system experience. Experiment 1 found that flow, as measured by a flow state scale, increased with initial exposures to a system but then decreased. Experiment 2 extended this finding and found flow followed a cyclic pattern over multiple days of exposure. Experiment 3 examined how system aesthetics influence user needs and found that aspects like graphics and perspective increased feelings of challenge and engagement. The findings suggest habituation of flow with repeated use and implications for using measures of flow and aesthetics in system design.