Continuity mistake: When Hulk is sitting in the treehouse, the tattered gym shorts he was wearing while battling Abomination are now pristine. (00:04:32 - 00:06:19)
Continuity mistake: When Gargoyle is looking at She-Hulk's car through a pair of binoculars, he is looking at it from a slightly perpendicular angle. When the shot changes, he is suddenly looking directly at her rear license plate, which would not only be impossible from the angle where he was standing, but even if he did move, the car parked directly behind hers would not allow him to see her license plate from a straight angle. (00:07:46)
Continuity mistake: When She-Hulk's parents come to console her, they are standing to her right, with her father standing to the mother's right. When the shot changes, they are both standing directly in front of her, and her father is on now on her mother's left. (00:08:35)
Continuity mistake: When She-Hulk is visiting Bruce in the treehouse, the holes in the floor caused by the Hulk's feet are no longer there. (00:08:49 - 00:09:53)
Continuity mistake: When She-Hulk is telling her parents that Bruce will help her, we see the Hulk sitting in the treehouse with his left leg sticking through the floor, and his left arm near the doorway. When the shot changes to inside the treehouse, his left leg is perched on the floor, and he is several feet away from the doorway. (00:08:49)
Continuity mistake: When She-Hulk is calling Gargoyle a vertically-challenged tree stump, her dress is colored pink, when it should be black. (00:11:15 - 00:14:45)
Continuity mistake: When Ogress is attacking Jennifer inside the dance club, the hair on her head and arms is black when it should be dark brown. (00:18:40)
Continuity mistake: When She-Hulk's high school classmates are shown in the car, the woman in the back waving the pom-poms is wearing a blue outfit. When the shot changes, her outfit is now purple.
Continuity mistake: When She-Hulk's high school classmates are waving goodbye to her, you can see the woman in the front passenger seat is sitting down. When the shot changes, she is suddenly slightly standing up.
Continuity mistake: When Ogress has She-Hulk in a bear hug while Gargoyle is saying he can restore her to her luster, the hair on Ogress' arms is the same color as her skin, when it should be a dark brown.
Continuity mistake: When Dark Hulk arms the nuclear warhead, the orientation of the timer is the same as the control buttons. When Banner disarms the warhead, the orientation of the timer is now upside down respective to the control buttons. (00:18:00 - 00:20:26)
Continuity mistake: After the alien entity has been purged from Bruce Banner's body, he is on all fours and tilts his head back, with the warhead behind him. When the shot changes, his head is pointing forward again and the warhead is now directly in front of him. (00:20:15)
Continuity mistake: When the alien entity transforms Bruce Banner's body into a purple-skinned Hulk, his hair also turns black. When the shot changes, his hair is back to being brown.
They Call Me Mr. Fixit - S2-E4
Continuity mistake: When Crusher Creel is jealously watching Bruce Banner giving Miss Allure a once-over, he transforms his hand into stone. When the shot changes, his hand is back to being flesh. Moments later when Miss Allure tells Crusher to take Banner shopping, his hand is stone again and transforms back into flesh. (00:08:45 - 00:09:26)
They Call Me Mr. Fixit - S2-E4
Continuity mistake: When She-Hulk is following Miss Allure's limousine, we see a shot of her hitting the gas pedal, and you can see the brake pedal next to it. When she is shown hitting the gas pedal again, the brake pedal is now missing and the gas pedal itself is larger than previously shown. (00:10:06)
They Call Me Mr. Fixit - S2-E4
Continuity mistake: After Crusher Creel breaks down the door to the warehouse, the shot changes and he and Banner are instantly standing just inside the doorway to the warehouse. (00:10:44)
They Call Me Mr. Fixit - S2-E4
Continuity mistake: When Crusher Creel first finds Banner in the building wreckage, Crusher is shirtless. When the shot changes, Crusher is suddenly wearing the tattered remains of his suit jacket. (00:17:42)
They Call Me Mr. Fixit - S2-E4
Continuity mistake: When She-Hulk enters Miss Allure's highrise by scaling the building and coming through the window, the window is instantly closed again when she confronts Miss Allure (note the glare on the window just over She-Hulk's right shoulder). (00:19:39)
They Call Me Mr. Fixit - S2-E4
Continuity mistake: After Miss Allure fails to hypnotize She-Hulk, the white of She-Hulk's eyes are briefly colored green. (00:20:02)
They Call Me Mr. Fixit - S2-E4
Continuity mistake: When She-Hulk goes flying off the ramp, you can see the based on how quickly the clouds are passing by in the driver's side window that the car isn't moving very fast. When the shot changes to outside the car, the rate at which the clouds move along the screen as the car flies through the air suggests it is now instantly moving a lot faster.
Answer: The Hulk is a giant brute who smashes everything in his path when he is angry. In Ang Lee's "Hulk," General Ross, played by Sam Elliot, explains it to his daughter.