The Mexican standoff

My wife's getting new glasses, and it made me think of the time I got new glasses, and got dissed.
Not a lot to tell at first, run of the mill experience, eye test, picking out frames, then I had to go kill a little time before coming back for my glasses.

So I pick up the glasses, and as I was waiting in line to pay for them, I noticed a sign on the counter that said that they would give you $5 if they forgot to give you a receipt.
I paid, they didn't give me a receipt, and I was quivering with excitement as I headed for the door!
I opened the door, stepped over the threshold and onto the sidewalk, and the door swung shut behind me! Cha-Ching! Score!

I turned around, swaggered back though the door, strode up to the counter, picked up the sign, and said, "you have to pay me $5 because you didn't give me a receipt!"
The girl at the counter explained that She didn't owe me $5 because the only reason she hadn't given me one was because she had forgotten to.
I said that it didn't say that on the sign.
So she put the sign away.
I said "I want my $5."

The shop girl held her ground, a Family of Midgets glowered at me, and a scruffy Marlboro-looking man said a bunch of derogatory stuff about me under his breath. Everyone was against me, and all I wanted was the measly $5 that this goofy little sign had butted into my life to offer me. A seething hatred hung heavily in the air...
"I want my $5... You had a sign that said I could have $5 if you didn't give me my receipt, and you did not give me my receipt..."

It was a Mexican standoff!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
(except none of us were Mexican)

"Ok!" she snapped at me, and printed up a receipt, with $5 discounted from the total...
I took the receipt and triumphantly strode out the door!

Then..."doh!"

so I go back in...

"Uh, yeah, so you didn't actually GIVE me the $5..."

Shop girl, Marlboro Man and a family of Midgets boring holes through me with their eyes...

I left.