The answer to all your computer issues (now including the caching issues on websites): Restart your computer

Versioning js and CSS files with get parameter

Actually that's pretty smart. People with no internet skill whatsoever usually flood the server with authentication requests. Asking them to reboot will reduce the amount of attempts (because the PC is restarting, duh), and thus reduce server load, while the problem solves itself out.

@Strannch LOL! This actually makes sense.

But, when they realize that restarting didn't fix the issue on website, they are going to be sooo pissed!

Its actually a great tip, as some browsers have an extra process running, for example IE, and just closing all browser windows wont "end the session". Restarting the computer will force a session close.

@sebastian Why do I even have to close the browser in the first place.

You want me to close all my open tabs, my working applications, vagrant machines and all docker containers, just so I can sign up on your website!! Sigh!