Self aware?

I hope you all remembered that Be 'Nice to your Liver Day' was today.
Recently I've been thinking about knowledge. In particular self knowledge and awareness. There are some  (mentally) disabled people who although being quite severely affected are under the impression that they are not very disabled at all. This got me to thinking, how can I measure how disabled I come across as, as if I'm more disabled than I think I am, I'd be unable to know how disabled I am. Most people can judge themselves using what is known as a human mirror, where we base our self image on how other people react to us. However, people on the autistic spectrum aren't very good at doing this. Personally I believe I'm not too bad at it, but I can't really tell because the only reason I think I'm reliable at seeing my 'human reflection' is based on what I see in said reflection, so if I'm worse at reading it than I thought, I wouldn't know. This extends to all points of reference to how socially and emotionally able I am, as I can't trust my own judgement when trying to work out if I can trust my own judgement. It even means I can't necessarily accept it if someone tells me I seem relatively (I use that word to an extreme here) normal, as I wouldn't be able to tell if they were merely being condescending.
However, what is more interesting is that this also applies to you. You might reason that you have no reason to think you are any less than average, but that's just what someone who is deluded would think, isn't it?