Oh, so many examples come to mind! Here's two:
Pre-mustachian, we were barely out of college & had school loans & credit card debt. Hubby picked the setting, and I handed him a faux diamond to put in it. Shortly after the proposal, he informed me that he intended to eventually upgrade to the real thing, a $6K stone! I told him no way, I'd never feel comfortable wearing $6K on my hand. My faux rock still shines as brightly now, and the sentimental value is far more than $6K!
A neighbor just finished paying off his vehicle, and wanted to replace the car payment w/a hot tub payment. As both he & I have medical issues that benefit from a therapeutic hot tub, I wanted to help him out, so I showed him our refurbished tub, which could be had for 1/5th the cost of new. He was very interested, but in the end, he went to a showroom and bought a top of the line hot tub. His rationale was that everything is under warranty for the first 5 years, so he wouldn't have to worry about repairs during that time. It's been 3 years, and the repair guy showed up last week. Neighbor was then ranting about how the warranty only included parts, not labor, and the labor bill was very expensive.
Sigh...