Each villain became a villain for different reasons, but all stem from the same issue…parents.
Regina had an emotionally/physically abusive mother, and a weak father who did nothing to stop it.
Cora had a miserable life with a drunk of a father.
Rumple had the absolute worst father ever on this series who abandoned him.
Hook seemed to have a good life, and I assume his parents died when he was young.
Zelena had a good mother who died later, leaving her to an emotionally abusive father.
Out of all these villains…we can all pretty much sum up that Zelena has more screws loose than the others, but my question is why? What makes her so different that she has to be crazier…I just didn’t see the reason behind her wickedness besides jealousy and greed.
"If you go as far as you can see...you will then see enough to go even further." - Finn Balor