This is what finally got me to switch to Linux years ago. Back when Virtual machines were relatively new I was messing around with them and hated having to scrounge for windows licenses to use in the VM's. (Back then you had to enter the CD Key to begin installing the OS, they didn't have trial periods, or 'activate later' options) started using Linux in VM's to try it out, and boom 15 years later, I'm never going back.