"Anything which should be done, if done as it should, to the extent to which it should, in the place where it should, at the time when it should, and in view of the end for which it should, is called good."
Kind of explains why the distinction between good and bad remains a grey area for some.
p.s. Defining 'good' has been a problem for philosophy, see e.g. discussion of Moore's naturalistic fallacy---a problem in trying to define good in terms of something else. Sam Harris' The Moral Landscape has been the most useful book for me on understanding ethics and what good means.
 https://www.britannica.com/topic/naturalistic-fallacy Not sure if that's the best link for the topic, but it's a start.