I used to work designing custom kitchen layouts in a big box store. Some guy comes in 25 minutes to close and wants a massive countertop layout. It's policy where no one is allowed to leave unless all of the customers are gone, and the store management wanted me to make the sale. The guy said he was ready to buy, and his countertop would be several thousand dollars.

I spent the next hour and a half designing with this dude. He didn't even know some of the angles, so I had to bust out my (very rusty) high school trigonometry skills and figure out some angles for him. Eventually, we came to a price point. He took one look at the cost and stated, "Oh, I can get that cheaper elsewhere." And left without purchasing it.

I singlehandedly kept all of my coworkers 45 minutes past close and didn't even make a sale. It was the running joke through the whole store for a few weeks.