The younger swimmers have so much energy and enthusiasm. It is lovely to watch them. The photos too are priceless. I have photos of my own swimmer from when she was doing the fly and breast at 8 years old. We giggle at them now in comparison to her more recent photos were her technique has greatly improved.
For me, the fun part is capturing the emotion. The concentration behind the blocks. The nervous warm up. Holding the stomach to stop the butterflies. Sometimes, you can literally see the swimmer run the race through in their heads.