Google Glass
It's almost amazing how badly Google underestimated the attractiveness of Google Glass because the company was so committed to the new technology. After a brief test run with a small group of users, it was made available to the general public in 2014, whereupon the concept was quickly and unreservedly destroyed.
The concept behind Google Glass was both futuristic and useful. It was a headset that could be worn and resembled a pair of glasses. It had a lot of the features of a smartphone, but rather than requiring you to lift your phone and look at the screen, it put everything you needed in front of you. On paper, it nearly seems obvious why it was thought to be a brilliant idea.
What Google failed to anticipate—or perhaps they simply underestimated—was the extent to which those who didn't want that technology also didn't want other people to have it. If a creep is filming you on the train or even your kids playing in the park with a cell phone, at least you can see them doing it. How would anyone know if someone were using Google Glass to record them?