CNN has a list of their biggest tech "fails" of 2010, and the number one spot is the iPhone 4 antenna issue, aka "antennagate." Perhaps it was inevitable that the hubris of Apple's past decade would eventually catch up with the company.
Antennagate, as you may recall, was the issue around a precipitous drop in "bars" (the apparent reception on your iPhone) when the iPhone 4 was held in the "death grip." I experienced this on launch day and even had a few dropped calls when putting the lower left corner of the phone into my palm. But according to Apple in a rare press event to address the issue, less than 1 percent of iPhone owners actually reported this issue.
Nevertheless, CNN also notes that the issue has quietly faded away (after a bumper giveaway and OS update or two), and the phone is still a huge seller. The fail appears to have been a mere blip. It certainly didn't have as widespread an effect as the Gawker media sites being hacked, which came in at number seven.