I love the difficulty of animal photography because of how much privilege I feel when I manage a decent shot.
With some animals, the fun is in playing the game of patience, waiting, and slowly getting closer until your camera lens is so close to them they can touch it. Often I don't realise I got so close until I peak out of my camera.
With others, the challenge is in capturing an image while they are on the move. They can be incredibly fast and never return. It can feel terribly disappointing or frustrating when you miss a shot, may it be because something got in the way or the animal was too fast.