Until this update, I had a large network of client sites managed by the Jetpack Manage module. I set Jetpack as one of the plugins to to auto update (It's partly created by Automattic, so it's gonna be rock solid, right?). That day, I woke up to a sh*t storm of angry clients saying that their site is broken. Loss of income, you broke my site, yada yada yada...

Lesson learned: the world is not yet ready for WP plugin auto updates.

Luckily I was able to fix the issues within 15 minutes. I've lost the trust of a lot of high profile clients now though.

I can't complain though, it's a free service after all. As I say, lesson learned.