Wesley finally gets pushed to the limit by his big, fat, obnoxious boss and tells her off. And then he immediately tops it off by smacking his sorry excuse of a friend in the face with a keyboard, knocking out one of his teeth which goes on to spell "Fuck you" with the keys that come flying off.
Also of particular note: Wesley lays siege to the Fraternity fortress. With exploding rats.
During this scene, he shoots a guy through the eye, jams his pistol through the hole, and uses his body as a shield while continuing to kill.
The Good-bye bullet scene, courtesy of Fox.
And the final scene where Wesley lures Sloan out into the open with a decoy and shoots him in the brain. He then proceeds to break the fourth wall, asking the audience, "What the fuck have you done lately?"
Don't forget the fact that he shot it over several miles through cars and windows.
Not to mention that the bullet nearly hit both his former best friend and his boss on the way to Sloan.
And again in the ending. "This is just a motherfucking decoy."
Most cutscenes in Weapons of Fate, right to the end when Wesley defeats the Immortal.