Harry Potter makes for an interesting protagonist. For one thing, he is a wizard who grew up in the Muggle world, leaving him completely perplexed as to the goings-on of the wizarding community. This in turn makes him a great entry point for the series' lore, as readers and viewers learn alongside him.
Furthermore, Harry is a flawed and relatable character. He is never the smartest person in the room, and he often requires a lot of help from those around him. The decisions he makes are always interesting - and not always perfect.
Best: Shunning Draco
Almost immediately upon arriving at Hogwarts, Harry is accosted by Draco Malfoy. Draco approaches Harry in an off-putting manner, making rude and disparaging comments towards the Weasley family. Harry, having already befriended Ron on the Hogwarts Express, essentially tells Draco to shove it and refuses his handshake.
It's a good thing. It would be a very different story indeed if Harry had befriended Draco instead of Ron - especially when considering that Harry was almost placed in Slytherin.
Worst: Antagonizing Ron
Deathly Hallows sees a vastly different interplay between Harry and Ron. Throughout much of the series, Ron remains the primary comedic relief, and he and Harry continuously get along - minus a brief falling out in Goblet of Fire. In Deathly Hallows, Ron falls under the influence of the locket (not to mention the unending stress) and turns ugly.
Harry, knowing that Ron is stressed, continues to antagonize him anyway. This results in the departure of Ron, which could have proven very unfortunate if Ron had not been given the deluminator.
Best: Going Into The Chamber
Harry is rarely the smartest person in the room (given that he's almost always with Hermione), but he is arguably the bravest. This is exemplified at the end of Chamber of Secrets, when he decides to enter the Chamber (with a very reluctant Ron and Lockhart). It was a great decision.
Had he not, Ginny would have died, the basilisk would remain free, and Voldemort's spirit would have been freed. Luckily, Harry does enter the Chamber, saves Ginny, and kills both the basilisk and Voldemort's young Tom Riddle spirit.
Worst: Sectumsempra
Half-Blood Prince sees Harry falling victim to the allure of the titular character. Ignoring Hermione's pleas to throw the book away (thinking she's just jealous of his continued potions success), Harry continues to fall into its gaze. It gets so bad that he eventually tries an unknown spell on Draco after Draco attacks him in the bathroom.
Unfortunately, the spell proves incredibly dangerous and nearly kills Malfoy. If it wasn't for Snape's quick intervention, Harry may have been a murderer.
Best: Not Going Along With Umbridge's Propaganda
Order of the Phoenix introduces who is arguably the most detested villain outside of Voldemort - Dolores Umbridge. Umbridge is sent to Hogwarts by the Ministry of Magic to quell "rumors" of Voldemort's return by enacting propaganda. Fortunately, Harry isn't having any of it.
He knows for a fact that Voldemort has returned, and he publicly clashes with Umbridge and refuses to go along with her nonsense. His behavior further sows dissent, and Hogwarts actively fights back against the shameless propaganda that is fed to it.
Worst: Letting Cedric Touch The Trophy
Harry means well, but his actions sometimes result in disaster. Such is the case in the climax of Goblet of Fire. Ever the noble hero, Harry allows Cedric to touch the trophy with him, thereby making them both winners of the Triwizard Tournament.
But what Harry didn't know was that the trophy was actually a portkey and that it would take them directly into the hands of Voldemort. The meeting results in the death of Cedric, and Harry is left with incredible feelings of guilt over his murder.
Best: Faking Death
In Deathly Hallows, Harry uses death to his advantage. He approaches Voldemort in the Forbidden Forest, allowing Voldemort to kill him. However, Harry remains alive owing to the protected blood inside Voldemort, and Harry fakes his death to ensure age back to Hogwarts in the arms of Hagrid.
Once there, Harry springs back to life and runs back inside the castle, stunning Voldemort and allowing for the eventual battle in which Harry would defeat the Dark Lord once and for all.
Worst: Falling Into The Ministry Trap
Order of the Phoenix sees Harry at his most irritable and easily manipulated. Voldemort takes full advantage of this. He sends a vision to Harry depicting the torture of Sirius inside the Ministry of Magic, prompting Harry and company to flee Hogwarts and enter the Ministry.
Of course, this was nothing but a trap, and Harry fell right into it. Harry's group engages in battle with the Death Eaters, and Sirius is eventually killed by Bellatrix. Once again, Harry's good-natured but naïve decision resulted in needless death.
Best: Going After The Horcruxes
Perhaps the best decision that Harry ever made was to go after Voldemort's Horcruxes. This certainly proved a daunting task, especially after seeing what it did to Dumbledore in the cave. But ever the brave boy, Harry soldiered on and went after the Horcruxes with the help of Ron and Hermione.
This decision not only resulted in Voldemort's death, but the very end of the wizarding war. Harry is a savior, and his decision effectively saved the world.
Worst: Snapping The Elder Wand
The Deathly Hallows ends in a surprising and somewhat perplexing fashion with Harry snapping the Elder Wand in half and throwing its remains off the Hogwarts bridge. This breaks from the source novel, in which Harry repairs his original wand with the Elder Wand and places the Elder back in Dumbledore's tomb.
Movie Harry fails to repair his original wand, ensuring not only that he remains wandless, but that the most powerful weapon in the world - one which could undoubtedly aid in the next dark wizard uprising - is destroyed.
