What's the difference between roast beef, pea soup, and glue?

The joke employs wordplay and misdirection to create humor. The initial question sets up an expectation of comparing three seemingly unrelated items: roast beef, pea soup, and glue. The punchline for roast beef and pea soup plays on the dual meanings of “roast” and “pea.” “Roasting beef” is a common culinary action, while “pea soup” humorously alludes to the act of urinating, using “pea” as a play on “pee.” The mention of glue is a red herring, meant to pique curiosity. The final punchline, “I knew you would get stuck on that,” cleverly references the adhesive nature of glue, while also acknowledging the listener’s confusion or curiosity about the glue’s inclusion in the joke.