ive never really thought about it. je ne sais quoi, I guess, but that's not a great answer.

seeming quietly clued in to the pervasive bs in the environment (a snobby answer, and i don't know how to put it in a tangible way).
mirroring me/appearing nonverbally receptive to my presence.
and being a little um, quirky, if in a good way (imo).