Every decision made in advertising is carefully considered, analyzed, focus-tested, ground into fine powder, tasted, reformulated, voted on, and finally presented to the disinterested public with the sincere enthusiasm of a municipal zoning hearing. We can only assume that it has always been so. Spontaneity and the vigor of genius are not only rare in the commercial world, but they are hated, all while paying lip service to the idea of celebrating the same. Trying to appeal to a young demographic has always been tricky. The Youth are cynical and mistrustful of The Man. Fortunately, there's always been the easy fall-back of tossing some slang around to show The Kids you're down with them. Problem solved!
As we have learned in the past, putting something in quotes is The Past's way of indicating that something is exciting and new. The Past is such a square. Anyway, here's the hottest slang of 1941 as demonstrated by this ad, explained for you denizens of The Future:
"got the mopes" - This means you're infected with Communism, and are banned from dancing, since it doesn't help The State. Also, erectile dysfunction.
"my eye" - An old Italian phrase meaning "I'll give her the evil eye, and her turnip crops will all be eaten by goblins, and she will live in the wilderness like a jackal." The Evil eye can be warded off by strategic use of The Corna, as made famous by Ronnie James Dio. Hopefully, Jill knows The Corna move.
"hot-head" - Someone who suffers from encephalitis, a brain fever that was common in the deprived swamps of wartime middle America. To be called a hothead was to be called a person of low class or of sub-average intelligence having poor decision making skills and poor memory. Encephalitis has also been tied to herpes simplex, making this an especially bad thing to hear from your girlfriend.
"of all the crust" - Identical to "of all the nerve". No longer in use. My mom didn't even know this one. Can also be used to imply the presence of herpes simplex. It's really not looking too good for Jim.
A collection of free things one could have hoped to find in a box of Pep.
Pep TV commercial, in which a guy picks up his date in wat is clearly a WWII era jeep, for some reason.
Another Pep commercial mentioning "that marvelous malty pep flavor." Yes, "malty".
UPDATE: I've just found "crust" in my slang dictionary, and the definietion is a bit roundabout, but it goes like this: 1."The head". From ca. 1870. Upper crust. Hence, off (one's) crust, crazy, or insane. 2. 20th century colloquial "impudence", "cheek": since early 1920s.