A new release of your web service has just rolled out with some awesome new features and countless bug fixes. A few days later and you get a call: Why am I not seeing my what-ch-ma-call-it on my thing-a-ma-gig? After setting up that zoom call it is clear that the browser has cached old code, so you ask the person to hard reload the page with Ctrl-F5. Unless its a Mac in which case you need Command-Shift-R. And with IE you have to click on Refresh with Shift. You need to do this on the other page as well. Meet the browser cache, the bane of web service developers!