Hopefully you only chmod’d your own systems. Early in my career, I worked on a project wherein we gave a contracting company root access to a computer they could use to test the software they were writing for us. One morning, they sent us a message saying they couldn’t log in. We looked at the computer and discovered it wouldn’t boot. Turned out someone on the remote team had chmod 777’d the entire filesystem. Of course we locked down their access after that.

It’s actually quite amusing to me that Wikipedia is an authority on “reliability”. It makes perfect sense, but can you imagine explaining that to a public school teacher twenty years ago?