I think of myself as a slow thinker and feel the same as many other comments on this post but I always but this down to being a visual mind and having to draw/picture everything to think it. So in my experience slow thinking is topic dependant; maths, conversations, even code are slow because I have to draw it in my head and it takes time. But give me a spatial/visual problem, like coming up with a plan for garden landscaping, organising room layouts or will this object fit in this space and it takes like 1 micro-second. it's weird.