Taken from a topic asking what the deepest moment in BIONICLE was:
Jaller whacking himeslf with a Kohlii sitck in the first movie.
...what? It's deeper than you think! It is a view into Jaller's psychology!
Before we study his behavior, we must examine the scene. Jaller has just unwittingly let Ga-Koro win. Prior to this, Hahli scores. Jaller says "Nothing gets past the Captain of the Guard... unless the Captain of the Guard wills it."
This is a hint to Jaller's relationship with Hahli. He puts down his Ta-Matoran loyalty, and although her scoring was no doubt due to a lack of concentration on his part, he forgives her and hints that it was intentional. However, Hahli scores again, winning against Jaller and Takua. Jaller then clubs himself in self-punishment.
The reason for his behavior is an emotional struggle between his feelings for Hahli and his Ta-Koro patriotism. He is known to be close friends with Hahli (but nothing more) and in MNOG II he gives hints to beat Ta-Koro. However, he is conscious of his duty to Ta-Koro and is sworn to defeat Ga-Koro.
His eventual rationalization of this problem is to allow Hahli to score yet win the game in a close match, then make up to Hahli later. Takua's lack of cooperation in this scheme (mainly due to his ignorance of it) causes it to backfire.
It is Takua's ego and desperate underconfidence which pushed him to make his EPIC FAIL move. Jaller, having attempted to reconcile his love for both Hahli and Ta-Koro, realizes the riskiness of his plan following Takua's EPIC FAIL move, and swiftly goes to work trying to beat Ga-Koro. Unfortunately, Hahli scores again and wins the game.
Jaller, anguished over Ta-Koro's defeat, blaming himself for the defeat (while upset at Takua for his EPIC FAIL move), and realizing the futility of it all, clubs himself. Stunned by the blow, he then questions his own intelligence and starts blaming Takua in his mind. Desperate to save his reputation, he nobly gives a low bow, dropping the Avohkii and setting the movie's plot into action.
Thus, whacking yourself in the head can be an important event and makes good philosophical debate matter.
And now you may enjoy my funniest post ever. 8D