1) It is far better to be on your own than with someone just for the sake of not being alone. That applies to friendships as wells as relationships.

2) To proclaim my understanding and competence on a subject, and then change my mind on it because my understanding was shown to be incorrect, it’s embarrassing for me, especially in public, as I fear it makes me look stupid. I prefer to avoid this and usually wait until I am sure of my understanding and knowledge before I start talking about it.
Agree.

3)I am naturally sceptical of second-hand information and whenever possible prefer to trust my own experience to reach a conclusion about something.
yes

4)If I need to learn something quickly, my first instinct is to ask someone I see as knowledgeable on the subject, rather than find my own way through it in books, the net, etc.
I usually figure it out on my own cause it's too much effort to track someone down and coordinate our schedules. It's way easier to go to the library or just fiddle with it until I can figure it out.

5) I have a very good idea about my level of sexual attractiveness (or lack thereof) in relation to others around me.
yes.

6) Especially in moments of crisis, I am inclined to be paralyzed by indecision and tend to wish, later, that I had acted more quickly.
usually, yes.

7) I worry far more about appearing stupid and/or ignorant among others than I worry about being awkward when dealing with people.
yes.

8)On the contrary, I usually tend to think I am already doing, or have already done, enough anyway – unless it is something that depends on a very specific standard that has to be met, in which case I meet it.
yes.

9) I respect, even admire, people who don’t back off from confrontations, even physical ones, and who take physical risks (not necessarily at the level of some Jackass stunts, but I think you get the idea).
yes if it's to protect someone or for a good cause. I look down on people who climb Mt. Everest just to say they did it, putting other people's lives at risk who have to then rescue them. that's silly.

10) I enjoy poetry and often wish I could write it myself.
I do write it myself.