"My Cousin Vinnie"
For me the two scene stealers are Marisa Tomei's court testimonies.
1. Ms Mona Lisa Vito is an expert on "General Auto Knowledge".
How to qualify an expert witness?:
My Cousin Vinny (1992)
D.A. Jim Trotter: Now, uh, Ms. Vito, being an expert on general automotive knowledge, can you tell me... what would the correct ignition timing be on a 1955 Bel Air Chevrolet, with a 327 cubic-inch engine and a four-barrel carburetor?
Mona Lisa Vito: It's a bullshit question.
D.A. Jim Trotter: Does that mean that you can't answer it?
Mona Lisa Vito: It's a bullshit question, it's impossible to answer.
D.A. Jim Trotter: Impossible because you don't know the answer!
Mona Lisa Vito: Nobody could answer that question!
D.A. Jim Trotter: Your Honor, I move to disqualify Ms. Vito as a "expert witness"!
Judge Chamberlain Haller: Can you answer the question?
Mona Lisa Vito: No, it is a trick question!
Judge Chamberlain Haller: Why is it a trick question?
Vinny Gambini: [to Bill] Watch this.
Mona Lisa Vito: 'Cause Chevy didn't make a 327 in '55, the 327 didn't come out till '62. And it wasn't offered in the Bel Air with a four-barrel carb till '64. However, in 1964, the correct ignition timing would be four degrees before top-dead-center.
D.A. Jim Trotter: Well... um... she's acceptable, Your Honor.
2. Ms. Vito expounds on wheel differentials
Vincent Gambini: Ms. Vito. Did you take this picture?
Mona Lisa Vito: You know that I did.
Vincent Gambini: And what is this picture of?
Mona Lisa Vito: You know what it's of.
Vincent Gambini: Ms. Vito; it has been argued by me, The Defense, that two sets of guys, met up at the Sack of Suds (store), at the same time, driving identical mint green Buick Skylark Convertibles. Now, can you tell us, by what you see in this picture, if The Defense's case holds water?
Mona Lisa Vito: (Initally refuses to look at the photo.)
Vincent Gambini: Vincent Gambini: Ms. Vito - Please answer the question. Does The Defense's case hold water?"
Mona Lisa Vito: (Honestly looks at the photo)
Mona Lisa Vito: No! The Defense is Wrong!
Vincent Gambini: (Smiling, knowing he's on the homestretch now) Are you sure?
Mona Lisa Vito: (Also Smiling, releasing her bitterness) I'm positive.
Vincent Gambini: (Playing it up knowing the endgame now) How could you be so sure?
Mona Lisa Vito: Because there is no way these tire marks were made by a '64 Buick Skylark. These marks were made by a 1963 Pontiac Tempest. (Vincent Gambini is grinning now because he's got the lock.)
D.A. Trotter: Objection Your Honor, can we clarify to the Court whether this witness is stating Opinion or Fact?
Judge Haller: This is your Opinion?
Mona Lisa Vito: It's a Fact.
Vincent Gambini: (Playing it up, knowing where this is going, he saw it all earlier in two sets of photos) I find it hard to believe that this kind of information could be ascertained simply by looking at a picture.
Mona Lisa Vito: Would you like me to explain?
Vincent Gambini: I would LOVE to hear this!
Judge Haller (Slightly Shell-Shocked) So would I!
Mona Lisa Vito: The car that made these two equal length tire marks had PosiTraction. You can't make those marks without PosiTraction, which was *not available* on the '64 Buick Skylark!
Vincent Gambini: And why not? What is PosiTraction?
Mona Lisa Vito: It's a Limited-Slip Differential which distributes power equally to both the right and left tires. The '64 Skylark had a regular differential, which anyone who has been stuck in the mud in Alabama (scene of the movie) knows, you step on the gas, one tire spins, the other tire does nothing.
Someone In Jury: That's Right