Time is of the essence
Sometimes you need to act fast, or an opportunity might slip through your hands. I will show you three pictures where you will need to be swift.
Sometimes bugs and spiders can be a bit tricky to frame. They like to move around allot and that could make it hard to keep up with the focus, but also to get a good angle!
Focal Length: 180 mm
Aperture: f/25
Shutter Speed: 16/10 s
ISO: 100

The hardest thing when trying to take pictures of birds is to get close enough without scaring them away. If you don't have a telephoto lens with you or if you're not hidden from the birds line of sight. Then you're out of luck sadly.
Focal Length: 150 mm
Aperture: f/4.5
Shutter Speed: 1/50 s
ISO: 100
But maybe the hardest, at least for me, would be to capture flies and bees in a good composition wile still maintaining the sharpness and focus. In these cases, knowing what settings you need to have for the occasion is key. Take to long with the settings, then they might already have flown away.
Focal Length: 180 mm
Aperture: f/3.5
Shutter Speed: 1/1600 s
ISO: 100