Why Ubuntu on Windows?

For programming purposes, I prefer Linux to Windows. However, Windows is really good at entertaining and office works. Beside, Microsoft Office is the best office suit I ever have experienced, and OneNote is one of my favorite note-taking software. Not to mention my beloved Bilizzard games such as Diablo, Starcraft and other video games. A solution to integrate Windows and Linux in one machine is to install dual-boot. However, I am tired of switching between 2 OSs.