MacOS is required to develop - no questions asked

My home setup consists of many operating systems. We are working in various fields, mainly creating business apps.

So, the technological landscape is pretty clear for me: I need

1. Windows - because my clients have that most of the time
2. Linux - because the servers all run with it, especially the cloud ones
3. MacOS - because building iPhone apps needs it and the OS has significant market share (especially among those, who are willing to spend money on purchases)

I was never fond of statements like "Mac is better than Windows", for me it is a different system with different things to know. It has a completely different architecture than Windows and that might makes it better for developers. But for the user, who is used to Windows stuff, it is just a hurdle to migrate.

As nerds we must embrace the diversity - in life and in technology.

I always hoped (after our early Atari/AMIGA feuds), that developers and sysadmins will overcome that "my system is better than yours" nonsense between systems. 

In my opinion it is our task to make that stuff run as good as it can. I also think, if you promote only one system, you might just not know enough about the other.