The left brain (logical) -- right brain (creative) theory is a great metaphor for thinking about the real requirements of lean thinking. Because of its manufacturing origins, lean has always had a bias toward the left-brain requirements of analyzing and solving problems. However, as we started to expand lean into our non-manufacturing (service) environments, we failed to see the totally different nature of the work.
The continuous improvement focus that is needed on the shop floor needs to give way to the continuous learning requirements of our knowledge and service workers. While the left brain is great at seeing and closing gaps, it is not very good at seeing the larger patterns or enhancements that would delight a customer and differentiate a brand (the strength of the right brain). The simple chart below will hopefully start to illuminate the need to bring our "whole" brains to lean thinking.