Some insects are insanely difficult to photograph, at least for me.
For example, the painted lady caterpillars on our hollyhocks.
Partly it is because the larvae often spin silk retreats for themselves. Taking a photograph of any insect under silk is like taking a photograph through a fine-mesh cage at the zoo.
When I do find some outside their silken retreats, they are so spiky that it is hard to find the right depth. Do you focus on the spines or on the head? Add some wind moving the plant around, and it isn't pretty.
Well, at least not as pretty as a cooperative adult butterfly.
Do you have a photographic nemesis? What thwarts your attempts to take good photographs?