[wlesieutre]

If you have Steam set to remember your password and log in automatically, it's fairly reliable. If you prefer to not leave passwords remembered, Steam will not launch even in Offline Mode until you restore the connection and authenticate. This is by design.

http://i.imgur.com/NXCpk.png

While I understand the reasons for designing it this way, it's still very annoying to be caught off guard by it. I'm glad that nobody could get access to any actual account data like my friends list, time played, etc. But I'd much rather it be a system like the Mac App Store, where software will run no matter what once it's been downloaded, and running things I've installed is entirely separate from my account authentication and anything with personal information in.