The nipples on the mermaid are tiny details in some larger work. As is common in CLAWs jargon, the phrase can be used as easily to indicate respect (for obsessive attention to detail) as to mock (for creating irrelevant detail).
While painting wargaming miniatures at Bognor, Simon Dawson remarked to ElfBoy that he realised he had perhaps taken attention to detail a bit far when he found himself painting nipples on a mermaid on a shield on a tiny figurine.
It has nothing to do with the Starbucks mermaid.
<Gnome> confluence: it is completely ridiculous that we don't have a unified timezone <confluence> Yes. <Gnome> and get rid of this stupid daylight savings time <Gnome> businesses just open later or earlier, depending <confluence> Well, the DST is nipples on the mermaid.