The must-have Macbook app is Windows 10.
No joke, my 12" RMB has run Windows 10 since Day 1, it's been over a year with no issues, I'm a Windows guy, I have all the necessary and expensive Windows apps like Office, I have no use for Mac OS and don't want to run it, never have. My Macbook boots to Windows, I wind up with the great thin/light Apple hardware and all the Microsoft software I'm comfortable with.
My advice to you is to install Windows 10 as your first app and avoid Mac OS entirely.
BJ