The young lady looks a bit like Madeline Kahn.

Over the years I have travelled US 90 many, many times and I reckon I've passed the spot where this diner once stood. I wonder which town it was in?

[Opelousas. Owner: Mason Alasandor. - Dave]

Photo of a blackmail quality if guy was married.

Ruth is shocked that her boyfriend, George, showed up unexpectedly in the coffee shop. He was supposed to be in El Paso by now. George has been accusing Ruth of flirting with Charlie every time he's in town, which she always denied. He finally caught her red-handed and can't help but give her one of his famous smug grins. Charlie is pretending none of this is happening by eating soup without a spoon.

Vera, quit yer flirtin' and fill the napkin holder!

Habs is absolutely right. If you will note, the tongue on the nearest board is still visible. Most installers would have sawn that off to offer a smooth edge. Maybe he didn't have a power saw and was cutting the corner instead of the oak.

I'm surprised no one has commented on the jukebox 'remote' that she has her hand on. How much to play "That Old Black Magic"? https://en.wikipedia.org/wiki/List_of_Billboard_number-one_singles_of_19...

I used to frequent a diner who's whose bar tops were made from old bowling alley lanes ... looked just like this one.

That all-eyes-on-her truck driver bears a remarkable resemblance to a great 20th-century singer-songwriter and sometimes movie actor, Hoagy Carmichael (1899-1981).

Carmichael wrote one of the most popular songs/instrumentals of the 20th century, "Stardust," along with "Georgia On My Mind" and "Up a Lazy River." And, since this Shorpy photo is set in Louisiana, Carmichael had a 1932 hit titled "New Orleans." That one was considered a jazz standard.

5 to 1 her name is one we rarely hear now - Phyllis, Gladys, Dorothy (Dot for short!) or Frances.

Little missy has beautiful hands but she needs a fresh mani. Also she may have got into the poison ivy.

... that countertop looks like tongue & groove flooring to me.

There's a lot we could concentrate on here: I don't see any ashtrays (it's 1943, were they being rationed? how many points to get one?), those oversized salt-and-pepper shakers (or maybe that's not what they are? a metaphor for the Deep South?) ... but I'm going to zoom in on what's in front of everyone: the countertop. It seems to be laid up in individual strips; 100:1 today it would be covered in some kind of laminate (and if they opted for wood, a veneer would be used).