On February 4th, Jeremy Keith wrote a post on Google's "Download Chrome" button being broken:

By all means add all the JavaScript whizzbangery to your site that you want. But please make sure you’re adding it on a solid base of working markup. Progressive enhancement is your friend.

Google is hoping to track downloads using Javascript, but when that fails, it prevents users from successfully downloading Google Chrome. We can assume that Google would rather everyone be able to download their browser, regardless of whether their link tracking works or not. They took a shortcut that appeared to solve the problem, but it actually turned a minor issue into a major one, incidentally nullifying the sole purpose of the page -- to download Chrome.

This reminds me of an old electrical issue on Land Rovers. In the 1990s, vehicles started to install brake interlock systems that prevented shifting the car out of park without your foot on the brake. This is a great safety feature that surprisingly wasn't made a requirement until 2006. But instead of installing a separate mechanical switch to check if the brake pedal is down, Land Rover decided to re-use the existing switch used to activate the brake lights.

Unfortunately, if anything went wrong with the circuit running to the rear brake lights, it would prevent the vehicle from ever being taken out of park. The wiring harness running through the doors was not designed with the utmost reliability in mind because, originally, it was not servicing anything too critical. But by attaching critical functionality to it, they introduced an egregious bug.

That is exactly the sort of thing that creates a reputation for poor quality. To the lay person, why the vehicle won't shift out of park doesn't matter. All they know is that they are stranded, and that seems like something Land Rover should have cared more about. And to Google's users, why you can't download Chrome doesn't matter. All they know is that they are stuck using Internet Explorer.

These sorts of critical bugs are rare because basic functionality is usually completed first and tested often. That's why it is so surprising to find them coming from large organizations. But, apparently, even they need to be reminded of best practices: make sure the vehicle can stop and go before worrying about the blinking lights. And whatever you do, don't make the core functionality dependent on the polish.