Ask any quality manager and they will probably tell you that driving continuous improvement is a big part of their job. Sometimes, we'll take any continuous improvement we can get. However, I suggest that not all continuous improvement is good continuous improvement. So, what make continuous improvement "good" and more importantly what does not fit the bill?
Regardless of what your system of continuous improvement is, lean, or six sigma, the customer is at the center of it all. All that we do for CI should be connected to the customer in some way. The problem sometimes comes when we have a system for CI but we don't fully understand all of the elements correctly or we don't give proper guidance about what is off limits. I'll give an example. In a recent situation, I found that shop personnel had made a decision to stop doing some important quality checks on the product. When I asked why, I was told that they were trying to save time (one of the 8 lean wastes) and they didn't think the checks were all that important anyway.
After I parachuted back to earth from my launch into the stratosphere, I realized that what had happened was that some cursory training had occurred about lean wastes and that we should strive to eliminate them, then no guard rails were put put up to indicate what things would be off-limits, and so people were searching for ways to reduce cycle times and the quality checks were a convenient target for a couple of reasons. They are extra work to the process of building the product, they are non-value added (the customer does not want to pay for them), and no one told them they had to keep doing them. So the quality checks were stopped.
Only one problem, if we consider lean from the customers' viewpoint. They want a high quality product exactly at the moment they need it. Quality checks are not a part of that equation in an ideal world where quality is built into the product and the process. In the real world however, some non-value added work is necessary to ensure the customer gets the high quality product they are paying for. Its non-value added but necessary, sort of a necessary evil kind of thing.
So, not all CI is good CI. The only good CI is that which does not sacrifice anything that is important to the customer.