Nothing says true love like a Cubic Zirconia.
Diamonds are for chumps.
One episode had the devil working in a jewelry shop and he convinced the groom-to-be to not spend the bucks on a real diamond ring but go for the Cubic Zirconia ring as "no one will ever know the difference". When the groom strolls over to the Cubic Zirconia display, the devil convinces the bride-to-be that a man who would buy a Cubic Zirconian ring is not worthy of marriage.
Of course, the couple begins arguing & bickering...just what the devil (played quite well by Ray Wise) wanted.