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.

or

On the contrary, very often I need to be with someone as loneliness is unbearable. On such occasions, I can’t be too picky about who the “someone” is.
First one. I prefer being alone, most of the time.

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? Disagree? Neither? Etc --
Ugh. I'm never really certain how much I "know" about something. I'm always worried there's something I've overlooked, so I look to outside sources of information for reassurance, and I do get embarrassed (though I don't admit it) when I am shown to have been wrong.

I don't really know if this answers the question... I guess the answer is yes; I do wait until I feel like I understand something before sounding off, but I don't easily feel confident that I do know enough, yet sometimes I feel compelled to speak out anyway if I feel like someone has said something stupid.

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

or

On the contrary, I think any one person’s experience – including mine – may be too narrow or limited, and I prefer to broaden it by getting as much second-hand information as I can.
I'm very knowledge-seeking. I constantly look up words, definitions, articles, etc., of things about which I am ignorant. I don't mind secondhand information as long as the person giving it appears competent and isn't being a dick (and the information makes sense, of course).

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.

Agree? Disagree? Etc
Agree, and I think you can personally attest to this. It just seems more efficient to ask someone who knows, if they're available, instead of first delving into a book.

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

or

Hmm, no. I am never sure about such things.
I agree with the first part. I'm very aware of my strengths and weaknesses in this area.

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.

or

On the contrary, I am far more likely, on such occasions, to act impulsively and to later regret my decisions taken so rashly.
The second one, but I've sort of learned to keep a leash on myself, despite feeling the urge to shoot from the hip in many situations.

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

or

On the contrary, I don’t worry too much about appearing stupid/and or ignorant – I am more likely to worry if I am being boring, inconvenient, rude etc when dealing with others, collectively or individually.
The first one.

8)
It is a very common state of mind for me to feel that, whatever I have done with regards to a task, or when doing something for someone, I could have done just one bit more.

or

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.
The first one, and that's often led to obsessive-compulsive cleaning/organizing when I was younger (though I'm much better about this now).

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).

or

Sometimes I may even wish I was better in such things, but normally I think that those who take physical risks (or risk getting into physical confrontations) easily are just being silly.
The second one. Getting into physical confrontations, doing daredevil stuff, is extremely foolish.

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

or

Poetry may be nice and all, but it’s ultimately pointless – I prefer writings that actually communicate something in a more straightforward language.
No opinion. Perhaps a slight lean toward number 2.