I'm consistently amazed how well Google and Facebook are at staying up. They're two services that I don't think I've really experienced a broad outage. Of course with Facebook's data designs, there's sometimes quirkiness as a result, but it's rarely completely off for me.
Google, I think I've only really noticed it offline once in the past 10 years or so. Not complaining at all.
> [Google's infrastructure] delivers Gmail and other services to hundreds of millions of users with 99.978% availability and no scheduled downtime.
[1] https://support.google.com/googlecloud/answer/6056635?hl=en
PS. 99.978% availability translates as a downtime of ~ 2 hours/year total. Not bad! But it's when things break that we realize how performant and reliable they actually are.
Edits: various typos.