We just rewatched this a few weeks ago (I'd been gently prodding for it, and with the right friends & some beers my suggestion was approved), and I hadn't seen it in YEARS. I was a little surprised at how continuously delighted I was Your post hits most of the high points, but I am still not over "Double dumbass on you!" I keep saying it & then laughing about it.

You're right about the joy in this movie -- everyone is having such fun and enjoying each other, and I think that that is actually one of the most important, winsome things about Original flavor Trek, & one of the things that makes it work, still.