We all know about buyer’s remorse. Well it turns out “inventor’s remorse” is a thing too. And it appears John Sylvan, inventor of the K-Cup brewing system, has a major case of it. In a wide-ranging interview with the Atlantic’s James Hamblin, Sylvan admitted that he neither owns nor uses a Keurig, and even more tellingly, he sometimes wishes he had never invented it.

“I feel bad sometimes that I ever did it,” he told Hamblin.

Sylvan invented the K-Cup pods and founded the Keurig company to produce them in the mid 1990s. He eventually sold his share of Keurig to Green Mountain in 1997 for $50,000, the Atlantic reports. You can add that move to Sylvan’s list of regrets. Since then, according to the Washington Post, Keurig sales have grown exponentially every year, even topping  $4 billion last year.

Despite these strong sales, concerns about the product have grown recently due to Green Mountain’s inability to find a way to recycle the K-Cup pods. Although the company promises to make the pods recyclable by 2020, the amount of waste generated by them currently is astounding. Mother Jones magazine estimated that the 8.3 billion discarded pods from a couple years ago would wrap around the Earth more then ten times.

Beyond these environmental problems, Sylvan also laments the K-Cup’s expense. As a single-service delivery system for an addictive product, Sylvan likens K-Cups to cigarettes. And like individual cigarettes for addicts, the cost of those single pods can add up for serious coffee drinkers.

“They’re kind of expensive to use,” Sylvan said of the K-Cup. “Plus it’s not like drip coffee is tough to make.”

Inventor’s remorse indeed.