You go to login into your site and get a warning "Maximum login attempts exceeded. You now have to pass CAPTCHA"... A little strange but not unexpected, someone tried to brute force their way in. Then your password doesn't work and other things aren't quite looking right. You start to fire up FTP so you can delete config.php with DB credentials and then it dawns on you, this is the local development server because you changed hosts file to test something else. <Doh!>
Kind of like riding a bike and you go off the cliff, then you wake up. I've had that dream more than once when I was in my teens.