Comment on How Skyward Sword Should Have Ended - SPOILERS by MetaKnuckles
It was pretty mean of Link to just use Peatrice for gratitude crystals. I couldn't bring myself to make her face reality when I played, but either way you have to get her hopes up for nothing.
I dunno about you, but I certainly wasn't using her for gratitude crystals - my love was genuine! 
Yours was, yeah, but most people were like "Quest accepted: Toy with this innocent girl's emotions". Then they went and smashed the chandelier at The Lumpy Pumpkin and gave Cawlin's love letter away as toilet paper.