When I'm arrogant and when I'm insecure

I've always had a strange mix of being arrogant and being insecure, both of which can be extremely annoying. But I had an idea about what the difference is.

I think, like many stereotypical smart-as-children people, I expect to have exceptionally high talent. If someone tells me a puzzle, or sets me a challenge, I expect to be able to do it easily and have people say "wow, you did it ten times faster than anyone else". Even if it's something I'm not actually very good at, or even if I'm competing with people I know are better than me, my first thought is that I'll be the best, and I have to bring that back down in line with reality later.

But if it's something to do with existing knowledge, even a small amount of existing knowledge, I wall it off. I say "ah, Tammy is obviously the person who knows about X, there's no point me trying to learn, it's probably incredibly complicated". I don't think "I bet I could learn that easily", I think "where do I start"? Which is a real problem when I'm learning things, because if anything is at all practically difficult (not conceptually difficult), I expect to just never learn it without Making a Giant Resolution to Study it For Weeks, even if it turns out it's actually quite simple.

What taboos are there amonst my friends?

Because many things that are a bit outré in traditional society have wide acceptance among my friends, I tend to think of us as more accepting and less judgemental. And I think we are, somewhat, because many people make a genuine effort to be accepting of ideas even if they disagree with them.

But I think, like everyone, I've also trained myself not to notice when I'm not discussing something because it might be awkward, because your own taboos are often invisible to you. My subculture has taboos, just like every other.

It's hard to say what's a taboo, and what's just "people don't like it because it's wrong". People I know don't have much tolerance for factual assertions that seem spurious, so where's the dividing line? Maybe things that make people cross not just confused?

What ideas would I feel uncomfortable expressing, even if I believed in them? (Most I disagree with, but I think maybe the instinctive level of disagreement is too knee-jerk and often excludes some people.)

* "Bike helmets should be worn"
* "There are times windows is more convenient than linux"
* "I drink no-alcohol beer"
* "I drink decaff coffee"
* "I like Twilight"
* "I like Dan Brown"
* "I'm an observant member of a religion"
* "I support the conservative party"

Almost none of those apply to me -- but I'm embarrassed to consider which of my ideas might be taboo, because, by definition, that would create a giant argument of people telling me I'm wrong.

Which other ideas do you think might be taboo in this subculture?

Also see:

http://www.paulgraham.com/say.html, where he says "if you're not hidebound by peer pressure, you must have some beliefs which are unpopular in your social group, not just unpopular to wider society"

http://slatestarcodex.com/2013/06/30/the-lottery-of-fascinations/ says "he wishes people he knew were as accepting of people who don't like maths as they are of gay people"