Lots of feedback here, but I'll add mine as someone who is pretty capable with both the MacOS and Windows, and is sitting in front of a computer for a good 10 hours a day at minimum, most of which is in front of a Mac if I'm not repairing or doing admin work on Windows.
Personally, I've never heard anybody think of the MacOS as a friend, and I wouldn't call it that... but I can certainly see how someone might feel friendly toward the Mac experience as a whole--sort of a welcoming feeling when you sit down in front of your Mac to do something, particularly folks who use Windows at work and a Mac at home.
For me, the MacOS is pleasant, capable, and does what I ask of it generally the way I expect it to--it doesn't pester me or get in the way, it and the applications on it just function. When I need more out of it, that almost always seems to be there, be it through the terminal or a new or interesting tool to do what I want. The hardware, likewise, is unobtrusive but attractive (and, I might add, usually feels nice as well--try stroking some brushed aluminum some time).
In contrast, Windows usually feels, to me, like one of two things: Either a guy who wants to be your friend but just ends up annoying you by trying to do everything for you (the endless XP wizzards that make any moderatly technical task twice as time consuming as it should be), or a bureaucrat who seems to enjoy hiding vital features in hard-to find places (almost every server admin tool I've used--the most common tasks are usually in a dialogue box accessed from a 2nd or 3rd tier right-click menu).
This contrast leaves me feeling very friendly toward my Mac whenever I come home to it after working with Windows, which is perhaps where the comments you've heard come from.
That, by the way, is why I really use a Mac: I spend hours a day fixing other people's computer problems, so when I get home I'd rather have my computer just work.