Anxiety-driven counterfactual thinking can be a slippery slope. Building on the premise that both positive and negative emotions can impact creativity, the present study examines how trait anxiety, optimism, and other mental health factors like therapy experience shape outputs in divergent thinking (DT) tasks. Using an online sample (N = 647), the study introduces counterfactual DT tasks, where participants are prompted to respond to how a situation can either go in their favor (positive) or against it (negative). Participants generated more original responses in the positive counterfactual DT task versus the negative one; however, they generated a higher number of ideas in the negative task compared to the positive one. Both counterfactual tasks led to higher originality and fluency as compared to a real-world DT task. Trait anxiety, especially when combined with past therapy experience or a previous mental health diagnosis, increased the number of negative counterfactual ideas. In contrast, optimism acted as a protective factor, enabling fewer ideas in the negative counterfactual task when combined with past therapy experience or a past mental health diagnosis. Our study challenges the binary view of emotional influences on creativity, highlighting the role of individual differences and experiences in shaping creative outputs. Diversifying the counterfactual DT tasks and using more refined measures of rumination and mental health history can provide further nuance to this line of research between creativity and anxiety.