Complacency has been defined as “a feeling of contentment or self-satisfaction, especially when coupled with an unawareness of danger, trouble, or controversy”, alternatively (and very simply) as “contented self-satisfaction”. The cause of such a mental condition may be interesting but is of no concern here, instead we will consider the result, which is failing or neglecting to act in a manner appropriate to the occasion. A previous paper explored this under the heading of “errors of omission”, and experiments with two groups of engineering students showed such an error can occur. From the experiment five factors were identified as contributing to the error, and recent further consideration has suggested that complacency may be an overall factor relating the five factors together. This paper’s objective is to relate complacency with those factors, then with recorded industrial disasters, and finally with an individual case in which over sixty years of complacent acceptance of the long term status quo came close to causing a fatality. The result of this reasoning and examples, unfortunately, leads to a conclusion that seeds sown in the past can easily be ignored because there’s no evidence in the satisfactory status quo that they can come to harvest unexpectedly.