Whoever decided to have Obi-Wan's hair fall out of place to symbolize when he himself is falling apart is genius.
When he's fighting Maul, he doesn't want to defeat him, he wants to kill him. He's so angry, flashes of Qui-Gon lying lifeless on the floor go through his head and suddenly he's 25 again losing the only father he'd ever known. Suddenly, he's channeling all the rage of his youth and it consumes him because this isn't Maul versus Obi-Wan now, this is Maul versus a young man who'd never known loss like this.
Now notice all the lightsaber marks, and notice how they all come from Obi-Wan. Maul doesn't slash the wall. Maul has the advantage, he's calm, collected and he knew exactly what to say that would rile Obi-Wan, and it worked. All that trauma Obi-Wan went through with Qui-Gon's death, there wasn't a Jedi that could help him in the way he needed. So he buried all of it, but then Maul came back from the dead, and so did all that pain.
Maul still being alive isn't fair. It isn't fair that he got cut in half and was able to live when Qui-Gon didn't survive. Obi-Wan finds himself so angry because how does a creature so evil get to live and his master didn't? You see can it in his rage, it isn't fair, you can see the mournful root of his anger, it isn't fair, you can see it with each careless, striken blow, It isn't fair.
