...to be a companion?

In the Blink thread a lot of people are saying that Sally Sparrow would make a great companion & I must admit that I agree completely.
But what is it that makes her companion material? (other than being nice eye candy Dave)
Is it her talent to get in to trouble?
Her ability to tackle the situation once she accepted it?
Her intelligence & ability to stand up to the Doctor? (albeit on a DVD).
Her talent to be in the wrong place at the wrong time?

Could you be a companion?
Can you deal with a situation when thrown in at the deep end or do you freeze?
Could you stand up to an authority figure & ask for the facts?
Would you be in the wrong place at the wrong time?

I think it was the thought of the Doctor being in the wrong place at the wrong time that prompted me to investigate places as a kid. I was & still am a bloody nosey git & will look around any old house, castle, wood or grave yard if given half a chance. I would have been in that house with Sally in the 'blink' of an eye.
But would I make a good companion? I don't know really, I'd like to think so.
Would you?