Does anyone but me wonder what kind of girl Charlotte was before the whole witch thing?
Makes me sad whenever I start thinking about it...

She was a fat glutton... That's about all I thought she was. A greedy, fat, (Metaphorically though; anime girls are never fat unless they're not supposed to be important), and selfish girl.

I'm more thinking she just had a sweet tooth, kinda like Kyoko always eating, cause when we saw Sayaka turn witch, hers was based around music, which she loved thanks to that boy who's name escapes me at the moment, so I'm thinking Charlotte's witch form was based around the same idea, so I don't think she was fat or selfish

Wiki says that her wish might have been a cheesecake for her dying mother ("A line in the design for Charlotte's labyrinth in the Official Guidebook says "It's really a delicious cheese cake. My dying mother wanted to eat it, but maybe I should have cured her disease instead. However, that surely wasn't possible.""). Another speculation is that she was a cancer patient who wasn't allowed cheese, hence the "hospital-based labyrinth theme".