Question: Pam, Greg, and Kevin appear to be in their late twenties or early thirties, but Pam says that the movie "Top Gun" was very popular when she was dating Kevin. "Top Gun" was released in 1986; more than ten years before this movie is taking place. Because Pam was engaged to Kevin at one point (she also describes their relationship as "more physical than anything else"), they must have been legal adults when they were together. Why would the movie "Top Gun" have been "very popular" while they were dating?
Question: Why would Jack instantly believe the weed wasn't Denny's? Isn't he supposed to be a human lie detector?
Answer: Confirmation bias - he believes what he wants to believe is true, since he wouldn't want to believe his own son is a drug user, and wants to believe Greg is.
Answer: There are certain physical tells for when someone may be lying as well. This is what Jack is doing at the end of the movie when he's interrogating Greg at the airport: checking his pulse, monitoring his breathing, and looking at his eyes.
Question: Why was Greg surprised by the fact that Kevin and Bob went to lacrosse camp?
Answer: Greg was probably surprised at just how "richy" they really are. Because lacrosse camp seems like a really rich, preppy thing to do. But mainly, I think he was suprised because he did not know that his girlfriend's ex and his girlfriend's sister's fiance knew each other. He didn't realize how connected they all were.
Answer: Who says they had to have been legal adults to date when Top Gun was popular? They could very well have been teenagers and got engaged shortly afterwards. If Teri Polo and Owen Wilson are playing characters that were born the same years as the actors themselves they would have been 17 and 18 respectively when Top Gun was released. If they are playing characters a few years older than they actually are, which is entirely plausible, what Pam says makes perfect sense.
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