I was very fortunate with the people I played with in Vegas, both men and women. Only came across 1 real obnoxious guy and when he gave me bs, I gave it back. The being perceived as nitty thing I think is true and I use it to my advantage, especially in the UK. The guys at my local casino even joke 'here comes Kate, now, if she raises PF she has aces'. Wonderfully exploitable.
In Vegas, female+British accent+military = EZ game. Guys could not stop talking to me or asking about what I did. I'm pretty sure they folded in places that they otherwise might not have. That sounds kinda big headed - sorry, not meant to be.
A big difference I found though, is that there is very very little chat over here, whereas in America, people were pretty friendly. Not saying the table has to be super chatty or anything, just a general feel. Although, I think my home country is generally ruder then anywhere else I've been! lol
Whoever asked about the nervous thing (caveat: I'm a recreational player, nothing else) the first few times you look down at a monster, you will feel your heart race and feel like everyone has noticed, but it gets easier...plus, like someone else said, if you are generally feeling nervous overall, its tough to spot!