What is the most important objective that TQM, Six Sigma and Lean approaches have in common?

I agree with answers given by experts Mr. Vinod Jetley and Mr. VENKITARAMAN KRISHNA MOORTHY VRINDAVAN.

While TQM, six sigma and lean have many similarities, especially concerning origin, methodologies, tools and effects, they differ in some areas, in particular concerning the main theory, approach and the main criticism. The lean concept is slightly different from TQM and six sigma. However, there is a lot to gain if organizations are able to combine these three concepts, as they are complementary. Six sigma and lean are excellent road‐maps, which could be used one by one or combined, together with the values in TQM.

To maximize the Customer satisfaction process by identifying the Fitness to use the service or product as per  their satisfaction perceptions, Quality being the top most  priority.