Yeah, I find INTPs intriguing too! One of my good INTP (confirmed, yes- had her take the test too hehe) friend will literally hop over my fence and come see me at night. I don't know what it is, but I'm the one person who she trusts with her most personal thoughts, and the one person who she will even let visit her house. I care for her dearly and find her wanting to be around me adorable, because she's not that way with many people.
INTPs amaze me with their level of intelligence. They tend to be so discreet about it, in which I admire. My friend doesn't go around boasting what she knows and trying to act like she can one-up others.. instead, she's humble and has so many fascinating/HILARIOUS things to say. When she has a point to make, she articulates herself real well where it's easy to respect her opinions, and other people want to hear more about what she has to say.. Mi amor.