[stevep98]

> You are never asked to enter a password, or type in "Remove Everything" as a fail-safe.

Some people will still do that and be surprised at the result.

My dad once reformatted his memory card on his camera, losing all his pictures from his vacation. He wanted to 'Change the Format' of the image (why? who knows), but instead he reformatted the card. "Are you Sure? Yes!"

I once copied an empty partition over a full partition instead of vice versa. I knew I only had one copy of this important data, and was trying to back it up. Are you sure? double-check.. YUP!

[MartijnHoutman]

Well, I had that once on my old Canon DSLR. I really wanted to change the picture format from JPEG to RAW (CR2), so I chose the 'format' option. I got into the format card menu, so I wanted to get out. There were only two options: OK and Cancel, but the interface was so bad I had no idea which button was active and which was not (the colors would invert on scrolling). A 50-50% chance, and I chose the wrong option ;) Luckily it was a quick format, so a raw scan saved my photos :)

[seanwilson]

Being forced to type out what you're about to do for critical actions like "remove all my data" or "deploy to production" works in my opinion. A yes/no prompt doesn't because you can get trained to click past them without reading.