Background. This study examines how live stream shopping stimuli—such as streamer appearance, product preferences, scarcity cues, and gamification—shape purchasing behavior and post-purchase regret. It also explores the roles of cue reactivity, craving, and impulsive buying tendencies in influencing consumer decisions and emotions. Method. Two behavioral experiments and one electroencephalogram (EEG) experiment were conducted. The behavioral studies captured conscious purchasing choices, while EEG measured neural responses, providing insights into the cognitive and emotional mechanisms underlying live stream shopping behavior. Results. Consumers with strong product preferences were more likely to purchase when the streamer's appearance was less prominent, suggesting product-centric presentations are more effective. Cue reactivity and craving predicted regret for high-preference products, whereas emotional responses had less impact on low-preference items. Time scarcity produced a U-shaped effect, with both high and low time pressure increasing purchase intentions, while moderate pressure reduced engagement. Cue-triggered pleasure did not reduce regret, aligning with research on compulsive buying. EEG results showed greater alpha wave fluctuations in the control group than in compulsive and impulsive buyers, indicating stronger internal conflict between desire and self-control. Conclusions and Impact. These findings highlight the complex interaction of product preferences, streamer characteristics, and psychological factors in live stream shopping. Visual cues and scarcity significantly influence purchasing decisions, while impulsive buyers exhibit distinct neural patterns that reveal the emotional conflicts underlying post-purchase regret. This research advances understanding of the neural and psychological drivers of consumer behavior in live stream shopping. By clarifying craving triggers and cognitive conflicts, it provides a foundation for marketing strategies that enhance consumer engagement while reducing post-purchase regret.