Kids express frustration differently by age: hitting and tantrums when young, whining and sarcasm when older. Don't take it personally. These moments are chances to teach them how to process emotions.
Chapters
The first thing I tell you along these lines is that you should strive to never take your children's frustration or aggression personally, even if they're telling you in the moment that they hate you. Aggression is just a natural thing that occurs when a child isn't processing their frustration. The younger your children are, the more likely they are to hit and kick and bite and tantrum when they can't handle the amount of frustration that they're holding in their tank. But as they get older, they they're going to turn to things like whining and passive aggressiveness and sarcasm and using their words to hurt others. This is not personal, it's an eruption of emotions. If we take it personally, we are always going to go down the wrong road in how we react to them. Another attitude or mindset to embrace is something I've seen work for countless parents, and that is to almost look forward to your children getting very frustrated because you see it as an opportunity to practice getting that frustration out, which is great for everyone.