Nice thread!!
If this was a test I would fail miserably. I am friendly -(some mistake or assume flirtation) with the most people I meet. I'm generally pretty good a sensing and reading people - except in cases like this.
I rarely I mean rarely notice. My friends would be the ones who would ask me after 'How did so and so work out?', or 'What happened with ABC? She's likes you.' I would ask 'What makes you think she likes me?' - of course I get the 'Are you serious ? look -
For me to know if she likes me comes one of three ways;
1) My friends tell me
2) The person who is interested comes at me with a 2x4
3) We eventually figure it out.--- Needless to say this option is in the lowest rating.
Maybe if there was some kind of sensory - mood accessory or emotion bracelet that we can wear to help determine if we like each other.
Of course to be worn discretionarily - wouldn't want to give away signals 24/7