When interacting with surfaces, humans perceive surface attributes which are often accompanied by affective responses. Notably, rough materials tend to evoke unpleasant feelings whereas some soft materials are frequently associated with pleasantness. While the literature predominantly focused on the relationship between solid objects and pleasantness, our daily haptic interactions also include fluids. Here, our main objective was to explore the relationship between unpleasantness and perceived qualities of touched fluids. We created a stimulus set by varying fluid properties of real-life materials (e.g., diluting honey with water). Participants actively explored the materials without time or movement constraints. In a first presentation block, they rated the unpleasantness of the materials while in a second block, they evaluated the materials based on seven sensory adjectives. Principal Component Analysis on adjective ratings revealed the dimensions characterizing differences in sensory qualities of our materials: viscosity and slipperiness. Importantly, we observed a positive significant correlation between unpleasantness and viscosity while no correlation was found for slipperiness. Specifically, materials perceived as more viscous felt unpleasant, emphasizing the role of viscosity in affective responses during haptic exploration. Overall, the current study contributes to the broader understanding of unpleasantness by extending our knowledge beyond the traditionally studied solid materials.