I very graciously let a friend use my hallowed & fusty old Ubuntu-fuelled ThinkPad X60s to check her Hotmail account using Firefox. It all went without hitch, except for the snide comments about “PCs” in general (she’s a MacFan) and the inevitable first-time fumbling with the Trackpoint.
After a while I reclaimed the laptop and booted up a Windows XP virtual machine (using VirtualBox), so that I could run the Windows MYOB accounting software that my accountant uses. I set the machine to Fullscreen Mode to truly ensconce me in the Microsoft Experience®. Shortly afterwards, my friend resumed possession, booted up Firefox and continued her Hotmail habit. She didn’t even know it was a different operating system: Firefox was her interface.