Performance on crowd sourcing platforms varies greatly, especially for tasks requiring significant cognitive effort or creative insight. Researchers have proposed several techniques to address these problems, yet few have considered the role of affect, despite the well-established link between positive affect and creative performance. In this paper, we examine two affective techniques to boost creativity on crowd sourcing platforms - affective priming and affective pre-screening. Across three experiments, we find divergent results, depending on which technique is used. We find that not all happy crowd workers are alike. Those that are primed to feel happy exhibit enhanced creative performance, whereas those that merely report feeling happy exhibit impaired creative performance. We examine these findings in light of preexisting research on creativity, affect, and mood saliency. Lastly, we show how our findings have implications not only for crowd sourcing platforms, but also for other human-computer interaction scenarios that involve affect and creative performance.