I don't need to imagine it, this actually happened to me. OK, it was a bit more than 30 min, but I used Arch Linux back in the day, around '07. Coursework was due the next day and had loads to do. Was looking for a distraction so decided to `pacman -Syu` in the middle of the day. It completely borked my system. Didn't have enough time to fix so chucked in an Ubuntu CD and within an hour I was back with all my favourite tools.

It's very different when you own your tools rather than renting them.

I had the same experience with Debian unstable and tetex, cca. 2003. Don't upgrade your production system, a good life lesson.