Do you brew your coffee using those Keurig k-cups? The man who invented it is ashamed of his achievement.John Sylvan told The Atlantic that he sometimes regrets his invention because it creates too much waste and is bad for the environment."I feel bad sometimes that I ever (invented the K-Cup)," Sylvan said. "I don't have one. They're kind of expensive to use. Plus it's not like drip coffee is tough to make."How expensive? A 12 pack of Folgers K-Cups , for example, sells for about $6.72, giving you about 4oz of coffee. In comparison, a 33oz container of Folgers Classic Roast Ground Coffee sells for about $8. That's 8 times the amount of coffee for nearly the same price.But most Americans don't seem to care about the cost or the environmental impact of K-Cups. The Atlantic says K-Cup brewers are now in 1 in 3 American homes."It's like a cigarette for coffee, a single-serve delivery mechanism for an addictive substance," Sylvan said.Sylvan says his biggest regret is the environmental impact. The Atlantic says if all the K-cups sold last year were laid end to end, they would circle the Earth more than 10 times.But Sylvan can't do much about that; he sold his interest in Keurig Green Mountain in 1997 for $50,000. The company now makes $4.7 billion in revenue.