My only really good story from working in retail is of a dude who wanted to exchange a quart of rancid orange juice at Shaw's supermarket where I was a checkout clerk.
We weren't allowed to do returns and the service desk was closed, so I had to tell him to come back in 3 hours (it was like, 6 AM.)
He screamed "WELL I'M STEALING THIS QUART OF FUCKING TROPICANA THEN, CALL THE GOD DAMNED COPS."
And that guy is my spirit animal now.