I started to reply to an Ask.Metafilter thread, but realized my response was mostly about me and not really answering the question, so I'm moving it here, to my personal home for navel gazing.
The question was posed by a woman who said she had a hard time bonding with other women, due to some "unspoken rules" that always made her feel like an outsider; she said most of her friends were men, but she'd like to expand her circles. There were a lot of great responses in the thread.
When I was little, most of the other kids on my street were boys, so that's who made up my friend circles. My parents had no particular ideas about gender, or if they did they never communicated them to me, so I grew up with the frilly dresses and hair bows that I loved, as well as my favorite toys of cars and trucks and building blocks and chemistry sets and tools and a million books on every subject imaginable. My first close female friendships didn't happen until first grade. In high school, I spent most of my free time as the only girl (or one of a tiny minority) in a social circle composed primarily of very nerdy boys. Despite all my male friends, I was not exactly a tomboy, not least because a) see above about dresses, and b) I was terrible at sports, at least at male-dominated sports. I did dance and diving and gymnastics and later, in college, synchronized swimming (shut up, it is a REALLY HARD sport!) and could never quite bring myself to care about football. I like basketball and soccer well enough, but not to the point of following particular teams or rankings, and the fact that they both involve men wearing shorts probably says a lot about why I prefer them to fully-armored sports.
I think most people who encounter me in real life would say I definitely skew girly: I wear makeup (not a lot--according to some friends, not enough--but noticeable), LOVE high heels, wear a lot of skirts and dresses. That kind of thing.
What I'm saying is, I can hang with the ladies. I have a number of very dear female friends, some of whom are less outwardly feminine-coded than me, some who are more so. None of us are particularly concerned with each other's dress/makeup/habits/etc. We just appreciate who we are; the end. There are no weird unspoken rules, except maybe that it's fairly easy to spot people who are fake when you're surrounded by those who are living authentically as themselves. None of us are too fond of the fake people.
The ones who most frequently remark on my perceived lack of femininity are men.
Several males (spanning the range from first dates to casual acquaintances to good friends) have remarked that I come across as "too masculine." I regret not having followed up more rigorously, so I don't know exactly where that comes from. I actually have to constantly fight my girly instinct to play what I call "cruise director," making sure that everyone else is happy and having a good time and is completely unaware of my discomfort, even if it's killing me. (I lose that fight a lot; I'm trying to learn not to have it at all.) So, it's kind of a surprise when I hear that.
On the other hand, despite doing a pretty good job at performing socialized gender roles in many ways, I have no problems disagreeing with someone (especially if their reasoning is completely faulty and they are pretending that it's "logical"), and I guess I have some "unfeminine" hobbies and interests. The older I get, the less inclined I am to try to live up to someone else's expectations of me if they're far afield of my own, so perhaps that's a factor as well. I like to hash out ideas, so if someone is not much of a talker, they can probably feel browbeaten by my stream of words. And if they don't enjoy verbal sparring--which I like to think I engage in fairly selectively, only with people who seem down with it, but we all make mistakes--I suppose I can come across as aggressive.
I am also not the least bit interested in seconding someone else's power/control issues, as has been very recently reinforced for me. If you're not secure enough in yourself to engage with a world outside your comfort zone, dude, just because it doesn't fit your shaky self-image of success and masculinity, well, you can just get lost. I haven't got time for guys who need everyone else to play to their insecurities. Get some therapy.
I guess that's what makes me "too boyish," to some people.
There's no ultimate point here, except maybe that gender roles and expectations are weird. I do find it interesting to hear about other people's experience with this sort of thing, though, so share if you're so inclined.