on why the Nigerian spam scams are so over-the-top ridiculous

A summary and a link, HERE. (Hat tip, Graeme Wood.)

It makes perfect sense once you read the analysis. The spammers have to identify, from among millions of us, the tiny number of fools who are ultra-gullible enough actually to follow through on the requested fraudulent transactions. So in fact, it would actually be counterproductive to make the spam more believable. Better to snare those who are sufficiently un-streetwise to respond at all to something so ridiculous.