Something I noticed about Avatar. Jake Sully causes more damage than he fixes.
Think about it, he turned a peaceful race into warriors, managed to get two clan leaders killed in a matter of days, and caused the destruction of Hometree. As proven later in the movie, Navi arrows can penetrate the chopper's cockpits, but instead of letting the Navi get to their banshees, he tells them to run, ruining any chance of a counterrattack coming in time.
The only reason the Navi won was because the bloody tree decided "Fuck it, this guy doesn't know what hes doing" and sent an army of dinosaurs to kill everything.