when I ask someone to pass the salt, I don't require a history of salt-mining along with it.

But you do expect pure salt that isn't damp. Basic housekeeping.

What I mean by "lazy" is, just for example, when it came to a mention of the Easter Rising the chauffeur explains that he didn't get involved in it because it only lasted six weeks. In fact it only lasted six days. Hardly a difficult thing to get right, which would have actually helped make his remark more plausible, and so helped the plot.