In either case, you want to boot Windows 10 on your Mac. Maybe you really like Apple's hardware, but can't stand OS X. Maybe you're using a peripheral that doesn't play nice with virtualization (like some printers) or you want to squeeze as much performance as possible from a game. You can often get away with running Windows in a Virtual Machine using Parallels or VirtualBox, but sometimes that won't cut it. More often than not, this means running Windows on your Mac. While Mac OS X works well for most tasks, there are times when it just can't do what you want it to usually that's some application or game that just isn't supported natively.
