It's like asking which of your children you love the most (That's easy. None of the little ****s.)
Big kite. Light wind. Glass. Slicing along in perfect trim. Pure joy. Maybe stomp the back foot and blast upwind if the wind picks up.
Medium sized kite. A bit more wind. Still relatively smooth water. Slicing along. Carving gybes. Pulling off the occasional 360. Not getting spanked. More pure joy.
Smaller kite. Powered up. Carving hard and boosting off waves. Rarrrr! What a hoot!
Tiny kite. Big wind swell. S-turns on big waves. Dropping in to a stand up face. OMG!!!!! Ooooh. I made it. Yeeharrr!
PS The windsurfers have a thread on what song you sing when sailing. When I'm setting up I hum The Girl From Ipanema. In my head it sounds like lift music and it makes me smile as a I connect stuff and head to the water.
When riding I often end up with arms outstretched in the "Jesus" position. I can't help but let out a yell, and sometimes its show tune noises, or "The hills are alive with the sound of muuuuuusssssiiccccc."