As KFChimera said, Regina immediately apologized for snapping at him once in front of her mother. In private she was very kind to him. She treated him as an equal, and Daniel was the one person around whom she could really be herself. Had they successfully run away together in EF, she very well could have found who she was and have been happy. She wouldn’t have had Cora planting false ideas and trying to mold her into someone she wasn’t for a start. Daniel wasn’t like Cora’s drunk father, and the two could have found a way to survive and even thrive together. She could even have helped teach riding to young children. She wasn’t exactly unskilled herself. Plus, she was smart. Regina at that time didn’t care about riches or have any interest in politics. She seemed to value simple happinesses, the likes of which her parents didn’t have in their lavish home.
I think losing Daniel was in many senses Regina losing the opportunity to become self-aware. She lost her love, her only friend and confidant, and her freedom all at the same time. It’s a shame she went on such a dark and downward spiral afterwards.