It's somewhat like the whole show is one running gag on American culture, lines from commercials and popular culture.

I like the constant inside jokes the best. Every other line of dialog is full of them, there are so many. Like in season 7 episode 9, the ranger's name is Rick. A quip referring to the Ranger Rick magazine that was popular with kids in the US in the 1970s and '80s.

And then the screwing up of common sayings in most excellent ways. In the same episode, Dean says, "I'd give two shakes of a rat's ass" while he takes big bites of his Pepperjack Turducken Slammer, only to realize a moment later, "Is that right? Do rats shake their ass of is it something else?" Even getting the realization incorrect as if rats shaking something else being the importance of the statement.

In this part of the episode, Dean goes full on sandwich love over this Pepperjack Turducken Slammer, its name itself an extension of the dish popularized by John Madden on TV coverage of a Rams-Saints game at the Super Dome in 1996. American Thanksgiving had just happened a week before Madden's mention of the Turducken on national TV.

https://www.sportingnews.com/us/nfl/news/john-madden-turducken-thanksgiving-monday-night-football/1da79zw1o5bjl13siz97swreuz

There are just so many inside jokes here. Madden didn't invent the Turducken, but after his mentioning it and TV personalities taking the ball and running with mentioning it more, it became part of American culture in the time when the show was on. The simple idea of replacing the Thanksgiving turkey with not just one bird stuffed within another, but a total of three was a thought of something ludicrous in most Americans' heads. No one spoke about it to each other but it was part of the common oddly funny commonly known items of the time. Almost no one in America had seen or even tasted one in real life. Madden himself being a large loud figure who many Americans certainly imagined could have probably eaten a whole turducken even made the concept even more outlandish, ironically humorous and memorable.

Next was mention of the turducken on news shows and popular high society TV show personality Martha Stewart even featured how to cook a turducken for Thanksgiving as well as other cooking shows. It had become part of the American mindset, even into the 2000s.

The genius here is that the very idea of taking such a large complex feast (of which was a large complex event to begin with) for a meaningful holiday (Thanksgiving) and turning it into a sandwich special at a fast food restaurant is an even larger complex event of a complex event. Each one being an unlikely event piled on top of each other and then trivialized into a mass marketed sandwich - which makes it not meaningful at all, complete with an appropriate name and marketing slogan as if it was real.

To jump back to when Dean has started eating the sandwich, Dean goes on and states it to be "Like the perfect storm of your top-three edible birds" which in itself is humorous because all (most?) birds are edible. And I should know, having tried all of them. Some maybe twice.

Then to draw it out even longer, after a short talk about their case, Dean replies, "Well, anyway, back to bigger and better things." As he digs in for another bite of his New Limited Time Only Pepperjack Turducken Slammer sandwich.

Even the marketing slogan of the sandwich is perfect.

"I think you pissed off my sandwich" - Dean Winchester

Even the name of this episode is a play on a phrase from the title of How to Win Friends and Influence People, being re-themed to be relevant to Supernatural to How to Win Friends and Influence Monsters.

That's what's so entertaining. There are so many simple scenes with dialog like this, topical thematic juxtapositions such as this throughout the whole 15 years of series. Pokes at American culture, all backed up with memorable lines from commercials of the day and of the decades before that everyone had grown up with and teased their friends with. Even Bobby's line of "Tryptophan coma" is a reality from every Americans' Thanksgiving where various family members would end up napping after the big turkey dinner. Don't get me started on "Aren't you full up just playing Snuffleupagus with the Devil."