When I started shaving with a SR I had some irritation but have not had any in months so for me it was technique but I certainly believe that a poorly honed or stropped blade would do it also. Lather??? I really doubt that it would make a big difference. I have made some poor lathers as we all have and it made for a challenging shave but did not leave my face raw. To me, a really nice lather is about comfort, scent and closeness of the shave but not irritation JMO