Will Hunting grew upon the poor side of Boston; the Southie neighborhood. It's area for the working class, less fortunate and uneducated.
In the beginning scenes, we, the viewers are just getting to know Will. At first he seems like any twenty-year old 'Southie' Thug; violent and brash. Of those we've seen in the film, his violence is the most extreme.
One of the scenes, in which he spies and old school bully (Carmine) and decides to attack him, is a perfect example of his character. It shows that he holds grudges and is the type of person who can't get over past experiences. It emphasizes his bottled anger and violence as he continues to punch Carmine, even after he's hit the ground and can't fight back. Will's spontaneity and rashness is depicted when he suddenly stops the car to go and confront Carmine when he hasn't even been provoked.
We see the loyalty and trust between him and his friends as they all rush to his side without question and how they prevent him from murdering Carmine - only to save him from more trouble with the police.
However, this 'beginning' character is not all cheek and hostility. Soon we begin to see the intelligent, gentler side of Will that evolves throughout the film.
To my recollection, the first evidence of this, is shown in 'the bar scene' where interrupts a conversation between Chuckie (his best friend) and another man who is trying to impress a few girls with his intelligence. In this scene, Will manages to save his friend from embarrassment and finds himself engaged in a duel of intellect with the other man. From this, the viewer has a glimpse of the knowledge that Will possesses.
After the encounter with Carmine, we are taken to a scene...