As Artificial Intelligence (AI) technologies become more embedded in decision-making, understanding how individuals perceive AI across varying contexts is crucial for ethical and culturally sensitive adoption. This study explores how public attitudes toward AI, specifically acceptance and fear, are shaped by its autonomy level, task criticality, personality traits, and cultural context (UK vs. Arab). Using the IMPACT framework as its theoretical underpinning, the study examines the interplay between AI modalities (automation and criticality), Big Five personality traits, and cultural background. A total of 639 participants (316 British and 323 Arabs) completed an online survey, supported by vignettes and scenarios, assessing attitudes toward four AI designs: low automation/low criticality (LL), high automation/low criticality (HL), low automation/high criticality (LH), and high automation/high criticality (HH). Participants rated the perceived impacts on well-being and ethical concerns for each AI scenario. In both samples, perceived well-being was positively linked to AI acceptance, while ethical concerns were strongly correlated with AI-related fear. In the UK, well-being was lowest for the LH modality. In contrast, Arab participants rated well-being higher in the LH and HH modalities, suggesting more optimism toward AI autonomy even in critical use cases. Ethical concerns were highest in HH modality for both groups. Personality traits influenced attitude but only modestly, with agreeableness predicting higher well-being in low-autonomy modality, and openness and extraversion contributing positively to specific modality. Neuroticism was linked to lower well-being in HL modality. This suggests that personality influence, although modest, depends on AI design.