Hitting when frustrated, told no, etc. failing to observe basic rules, particularly in other people's houses, silly habits (current annoying attention seeking one is licking people)? Making a mess at the table. And countless other things. And yes, we do focus on the positive, there are clear consequences for things she does wrong, but it seems to have little or no effect. She refuses to listen, won't do as she is told.
Disclaimer: am having a bad day where I feel like a crap parent and really wish I hadn't signed up.