For reference: She waltzed into the North and demanded they change their ways to accomodate her. She bullied and insulted their leaders when she didn't get her way. She assaulted Pakku because he wouldn't do what she wanted.
She delayed the effort to defeat the Fire Lord by faking Appa being sick so that she could pose as a god in order to perform terrorist attacks on a local factory.
She told Sokka he didn't love their mother as much as she did because he wasn't interested in pointlessly seeking revenge after fifteen years and used bloodbending (previously and subsequently established as a terrible crime) on an innocent man.
And that's just the tip of the iceberg. And Ozai is supposed to be a terrible monster?
On the other hand, old lady Katara in Legend of Korra is cool. Helpful, supportive, not self-righteous and up her own ass with how great she is.
So I forgive her for being a psychotic b-word who should have been brutally murdered two seconds into the series.