Should drop a hint that less is more.
Or suppress a giggle

each time she settles on one.
Wicked!
I think everyone starts off trying all the styles, and the sensible folk come to realise you really need simplicity.
I've seen some terrible ones, all bells and whistles. And one on a very technical science subject, where they'd pretty much written the entire script, plus graphs, on each slide, in 8pt type, in yellow on a black background. The speakers had heavy foreign accents, so I didn't understand much!