That's just how she is: overconfident to the point of being arrogant, impatient and aggressive. I can't say I like such a personality, but you go to give this to the makers at least they didn't try to make an Aang-copy. You gotta respect that they now used a girl as a main character that's very different from Aang, instead of just going with another male hero. You also got to be fair, the reason as why many people don't like her personality probably is because she's a girl. This description I gave applies to hell of a lot of other characters like Madara, Vegeta and Grimmjow and isn't it a coincidence that it are these same characters who are always having placed the epithet 'badass' placed on them and are extremely popular?
Even though I have no proof for this, I assume that from a girl's point of view, Korra might appear much cooler.
Still she should have at least considered that if her father didn't got banned, he wouldn't have met her mother and she wouldn't have been born -.-'