The reason Jayden was so annoying is...
The reason Jayden Smith is so annoying in this movie is not because he's a child actor. Nor is it because he is black. Nor is it because he happens to be Will Smith's son.
It's the fact that he's a snobby little stuck up disrespectful ass of a child. You know the type of child who needs to be spanked some sense into? This is the type of child that will grate on anyone's nerve whether in a movie or in real life. And to be honest i don't even blame the kid as it's mostly 99% of the time the fault and complete utter failure of the parents. These kids have parents who don't know how to properly raise a child--to raise a child to be respectful and have some basic goddamn decency and manners in civilized society. Again in real life this would be a torturous affair to be subjected to bear witness. And unfortunately in this movie we are forcefully subject to this abomination of cringe the whole way through. Of course no one's going to like this "character".
What can we take out of all this? Do society a favor and please raise your dang kids straight for the love of God. Don't be a pansy. It takes guts and action to be an adult childbearer. Otherwise don't have kids.