Ma’am is an American expression. It’s understood, but sounds overtly American to British ears, like “U wot m8” does the other way around. You wouldn’t hear it at a British drivethru unless there was an American working there.

That said, the artist is British and the car looks like a squished Mk4 Ford Fiesta to me, which didn’t exist in the US but were everywhere in the UK.

So it’s probably a reference or quote of something.

@Brass Melody  
Or just a call about your car’s extended warranty.
 
(Not even running gags are safe.)

@TheDog  
That or that burger shop in Persona 5 saying you won their contest.

@Ardashir
 
Actually, you get a call from a man named Kenshiro who says this.
 
@ZhaoZoharEX
 
It’s from a comic from an artist named valecity.

@TheDog  
After you eat that, do you get a phone call from a cute Japanese girl named Sadako to tell you that you have only seven days left to live?

@TheDog  
Jesus, my arteries are clogged just looking at that.
 
Also, is your avatar from something, the artstyle looks familiar to me.

@fixman88
 
A Spongebob reference. It basically means:
 
“Double triple bossy” means 6, all-beef patties. However, adding a 4x4 (4 beef patties + 4 slices of cheese) it would be 10 patties. Grill them (replicating “burn it”) in mustard. Don’t forget to squash them down with a spatula first before grilling. Also, you’ll need to add butter. But not too much, as “axle grease” means butter and “light” means not too much. Hide the patties under American cheese.
 
Deluxe would mean iceberg lettuce, tomatoes, cheese (ignore this because we already used the cheese when grilling the patties), white onions, ketchup and mustard. Thinly cut all of these. Remember to get two lots of these to cut up.
 
“On a raft” means Texas toast, so cut 48 thick slices of toast (you might need at least 3 loaves of bread) which we will use later. Extra shingles means MORE toast to make. Also, for “shimmy and a squeeze”, you can either butter the toast, spread mayo on it or add special sauce. Or, if you’re that hungry, all three.
 
Now, “animal-style”, add all the condiments you have, more special sauce (if you have any more if you used some on “shimmy and a squeeze”) and add grilled onions and pickles.
 
The last part we need to do is “Make it cry”, which is extra onions. If you haven’t ran out of onions yet, you’re done. But you still need to make the actual burger.
 
By now, re-reading it, I’m assuming you’re saying “But Capprio! You forgot to add in ‘Let it swim’!”. Well, “Let it swim” isn’t important. It means to go, and I’m assuming you’re making this at home. So just ignore that.
 
 
And here’s a picture of what such a sandwhich would really look like.
 

@northern haste  
Ok, that was glorious.  
‘Animal Style’ I recognize from In-N-Out’s secret menu but I have no idea about the rest.

Glimmy looks less like she’s trying to decide what to order and more like she’s admiring the thicc curves of the intercom.

@SinnerWhoKeepsTrying1978  
I don’t think they are actually placing that order. However, the way they take so long feels like they’re ordering one of everything by name.

@Th3M4nW1thN0N4m3  
In that case, wouldn’t it be easier just to say, “Yes, I’d like one of everything please?”

I really hate when people take forever to order via drive-thru. It’s almost like they’re ordering one of everything.

Don’t be that mare, Starlight…Almost as bad as those who don’t order anything, just to pick off of their friend/partner’s plate.
 
@Background Human  

 
That Homestar reference

@Magic Nova  
I’ve been told by some other people with experience in the fast food trenches that it’s deliberate. These customers try to make everything as confusing as possible and then raise a fuss just to get a free meal.
 
The guy who shared that with me also spoke with glee of the crapstorm he saw when a manager who knew this scam caught them at it and got said customers arrested for abusing the staff. It must have been glorious.

@Ardashir  
This. People set their expectations for fast food way too high. Like when it’s late night and some customers complain that it’s taking more than three minutes for one person to make $80+ worth of food.

@Magic Nova
 
How about the customers who think they’re ordering fine cuisine, and take an hour or so to detail literally every single thing you need to do to make their ordered food perfect?
 
And then when the order is wrong they howl until you just give them the meal to be rid of them?

@Definitely Not a Pony  
It’s not helping Starlight here.

@Meanlucario  
So the big detailed menus they have hanging up at the drive-through are just decorative, as I suspected

Big Smoke:All you had to do was to order the damn food Starlight

What else do you expect? Your ice cream machine is always broken.

@northern haste
 
“We serve food here sir.”

I’m always super anxious people behind me and the worker will be impatient with me so I try to order as fast as possible. Sometimes I even order the wrong things. I don’t understand how some people can do this without anxiety. :P

@Definitely Not a Pony  
Online menus or going in to decide.

What is the point of having a menu if they won’t give you time to read it. It’s always so stressful. We’re not androids able to read a thousand words a second, nor do we have photographic memories.

Careful, or she’ll complain to the manager over poor customer service for interrupting her thinking