If you use desktop password manager app 1Password, this hidden shortcut may make you feel incredibly warm and happy inside: drag a login from 1Password to your browser's bookmark bar and you've now got a single-click bookmark login.
As Brett Kelly notes on Bridging the Nerd Gap, now any time you click that bookmark now, 1Password will automatically fire up and fill in the login for you (if you have the software configured to automatically submit login forms) and log you right in. This really is a beautiful timesaver.
(By the way, I did try this with many other people's favourite password manager, LastPass -- dragging sites to the bookmark bar and clicking the bookmarks to see if I got logged in automatically, but, sadly, it didn't work.)
The Super Sweet 1Password Trick You're Almost Certainly Not Using [Bridging the Nerd Gap]