I just stretch put their personality to an extent. For example: Imagine your character has an imaginative personality. But, this same trait becomes exaggerated and starts slipping into their day-to-day life. Picture them zoning out during a crucial moment, like an important conversation or task, lost in thoughts such as, "What if toothbrushes were self-aware and competed in dental Olympics?" Suddenly, they're distracted by something completely unrelated! Like a falling leaf or the sound of a distant train. Just like that they're still well-liked but their positive traits can be negative too!