Why? Simply because this is a euphemism for asking for a freebie, a handout or a loan that you never intend to pay. First made famous by the bloated nitwit 'Wimpy', a waddling loser with an eating disorder in Popeye comics, it is a metaphor for the financial irresponsibility that is epidemic in American society today.
You have undoubtedly seen these 'Check Cashing' businesses that have a habit of springing up in the declining parts of town. Well, what these leeches do is give the gullible and irresponsible dregs of our society ADVANCES on their next paycheck, at exorbitant interest rates, skirting the usury laws. Once they get their claws into you, you are doomed. Idiots do this sort of thing in order to support their lotto or cigarette habit.
"I'll gladly pay you Tuesday, for a hamburer today", simply put is spending money before you have it. -or- simply mooching.
The United States Federal Government churns out millions of dollars of military, welfare and other 'hamburgers' that it does not intend to pay for until next Tuesday. In other words, by your grandchildren.
A catchphrase coined by Whimpy in the old Popeye cartoons and comics. It was actually "I'll gladly pay you Tuesday for a hamburger today"
Basically, someone who uses this or a similar phrase is trying to get something on credit, and may or may not follow through in paying you back.
"Why pay Tuesday for a hamburger today?"
"Because food debt doesn't have interest."
if you can't afford it (whatever 'it' may be) now, why even get that shit? Originally a catch phrase from Wimpy on that ol' skool shit: Popeye the Sailor Man
Hey bro, spot me twenty on this sack?
Fuck you man! Why pay tuesday for...