I enjoyed lots of the gratitude crystal quests, but my most favorites are the ones you call Shotgun Wielding Father (my dad is in this game?!) and Cupid was Here. I like the first one since I enjoyed Peatrice's character a whole lot and really thought that it was a cute side quest, although I had to reject her since my father was watching me play the game and insisted that I not "cheat on Zelda". As for Cupid was Here, well, I think most people would agree that seeing both possible outcomes of that is just quite fun. I personally decided to get Pipit and Karane together, though, instead of giving it to the ghost hand. I also have to say that I really enjoyed the ones you named I Study Botany and Out Standing in the Field, as I thought it was fun to fetch the Kikwi and the Mogma from down below. Let's see, another that I would have to mention would be I Lost my Pet, as I loved the bug game and it was fun to have to play that to get Beedle's beetle back! :>