She does whatever she wants then she goes back to apologize to him ofc he forgives he's too nice then she does it again at some point
Example: It's like when someone cheats you forgive them (probably some people do) but then they do it again and you keep forgiving them they're not going to stop you're kinda giving them permission since you not doing anything about really.
Im not saying korra is a bad person she makes mistakes but she really didn't listen to tenzin
Things could've turn out differently especially in season 2 with vaatu and all.
People run over you when your'e too nice they take kindness for weakness i felt like deep down korra knew subconsciously or something like that tenzin would forgave her.