The Joke:
My wife asked me to put ketchup on the shopping list… but now I can’t see anything.
Here's the breakdown:
What the wife meant: "Add ketchup to the shopping list" (write it down so we remember to buy it)
What the husband did (literally): He physically placed the ketchup on top of the shopping list, covering it completely.
The punchline: Now he can't see the shopping list anymore because the ketchup is blocking his view of it.