He is a teenager. A lot of this can be excused as simple immaturity and he ends up "saving the day" in all 3 movies despite any flaws.

Heck, in the second movie it is right in the plot that overcoming his hangup with the whole thing about being called "chicken" presents a direct growth opportunity.

I agree he is far from perfect, but he makes right choices more often than not when everything is added up in the end.