To me, Lean Six Sigma is about challenging established truths by asking critical questions and require facts. Critical questions enable us to develop and innovate.
Critical questions can be perceived as criticism therefore it is important to focus on the process, not the person. If we ask questions because we are curious and want more knowledge, the chance of being heard is greater.
An established truth within Six Sigma is that six sigma process involves 3.4 errors per million opportunities. It is an established truth that I want to challenge.