Too many things, that it's so overwhelming to try and qualify all. There's so much wonder and beauty in the world. I've sat on responding on this thread because any words I put here will still feel inadequate. A few, anyway:
Lightning - from storm clouds; but also that moment when struggling to find something - an answer, or that moment some missing puzzle piece lands perfectly in place - that electricity that winds through the brain in that moment of Eureka. Or that lightning that seems to strike when hearing a new song that hits a rare kind of sweet spot - a kind of realization that there is something amazing within my narrow cross-section of perceived Universe that I had no idea could even exist! It feels like the highest calling, to be able to create something, some art or writing or music that conjures forth that lightning for others.
Arriving at the walking loop at the park on a chilly, misty morning and observing that I have the place to myself, and then jogging the entire time with no human distractions. My thoughts and ideas blossom best in solitude, and I love being in the rain but not getting soaked. There is a rare kind of beauty that I think few others see in those kinds of cool, gray mornings.
Night swims on weeknights in the summer where the suburban sounds are a bit more muffled than they would be on weekends - tracking fireflies in the woods and listening to the sounds of katydids.
The way the sky looks at sunset when conditions are just perfect. Vibrant and bold red-orange. Pictures taken have never done it justice and always look nice but still washed and pale compared to the real reality. "You had to be there in that moment and see it with your own eyes" stuff.