This interesting post on .NET and its development community really struck a tone with me.
The first idea that comes from this is that Open Source is the peer-reviewed journal of the very scientific community that is the Free Software movement. I'm not sure where I'd be today without Open Source software; not only because I use it almost exclusively and have centered my professional life around it, but also because without it I'm not sure I would ever have really been excited and motivated to write software.
The second idea comes from this comment on Hacker News:
Microsoft's development tools have never had any underlying principles other than: enabling people with minimal knowledge to get stuff done.
This is a perfectly fine attitude for a product, but if you are a software developer by trade, you might strive for something more than merely being proficient within a system designed for non-experts. The Unix philosophy is, famously, "Do one thing and do it well." The system of Unix made up of these solid unitasking components enables people with vast knowledge to do almost anything very quickly.