Last year me and my wife spent our summer vacation in Asprovalta, Greece.
I woke up early in the morning to capture the sunrise. I went to the beach and spent an hour snapping various phases of it. After I took enough photos, I started walking back to my room, but I kept looking for interesting scenes. I saw this kid running joyfully through the waves on the shore and his father calmly walking behind. The light was perfect, and they weren't looking at me (or else I wouldn't take this photo because I don't like photographing strangers without a permission). Luckily I had my 55-200 lens mounted and I was able to zoom in nicely and to catch this moment.
What makes you joyful like this? :)