A funny thing about 1-1 PMing/DMing is that — unless you are a terrible snoop* — you never see any but your own. You have no outside examples to draw on. Unlike conversation there's no overhearing a DM.
I suppose they could appear in a work of fiction. If I recall correctly Ward has a few of these in the prologue, Glow-worm. The Northern Caves probably had a few, too. But I wouldn't want to draw on either of those as positive examples of DMs.
Anyway, I don't like this not having examples business, and that is something to work with.