Normally the biggest problem I have with Windows devs is getting their code editors to do the right thing about line endings.

But I've worked with .NET programmers before over server-to-server integration and both times they had trouble seeing the programming world outside the tools and libraries MS gave them. One dev in particular was very naive about ways to construct and parse XML that the MS library couldn't handle or didn't like. It made for some frustrating debugging a few times...

Wade.