Consumers generally prefer certainty to uncertainty, which leads them to shun uncertain situations. This research demonstrates, however, that consumers facing uncertainty (rather than certainty) associated with a positive event (e.g., winning a lucky draw but not knowing the exact prize won) can experience greater, longer-lasting positive feelings. The sustainability of this pleasurable uncertainty effect hinges on the (right) level of imagery elaboration that consumers generate about the various possible favorable prospects of the event (e.g., imagining the possible prizes from winning a lucky draw). Findings from two experiments support the proposed imageability-based framework. (c) 2009 by JOURNAL OF CONSUMER RESEARCH, Inc..