Good-We were best friends for three years first (and I "loved" her for the last two of those years) so we just interacted very well together. Even when we were friends there was this unspoken sexual chemistry, it wasn't what we said so much as how we'd use different tones of voices with each other than we would with anyone else, and how we'd finish each other's sentences. I liked how she managed to be very sweet and nurturing while remaining generally detached and objective, which is not easy to do. She also had a very subtle vulnerability that most people probably didn't know about, but was obvious to me. It was easy for me to be her "white knight". She also had probably the best butt in the universe. If you'd seen it you would know why it was important enough to mention.
Bad-The main reasons it didn't work was that I wanted things to move quicker than she did, coupled with the fact that she constantly did things that filled me with raging jeolousy. Immaturity on my part may have aggravated it (I was 18) but she made no attempt to change her behavior despite being apologetic when I'd bring things up with her. We also had very different life plans in general, which makes me think in hindsight that it never would've worked out even if I had been more secure in my relationship with her. She was outwardly intellectual, but I honestly don't think she was actually very thoughtfull or even that smart in general. I also wonder if I was "acting" a little bit once I got into a romantic relationshio with her. She mostly saw charming, cocky ENTP MyName, or sweet and cuddly INFJ MyName. Cold, awkward INTJ MyName didn't come out as often around her. Some of that may have been her positive affect on my mood, though.
Good-Same hot chemistry as with ENTP no. 1, but not as devoloped because we hadn't known each other as long. We also had pretty much the exact same interests (Politics, economics/finance, art house and classic films, chess exc.) so we always had lots to do and talk about. She was also way more physically attracted to me than anyone I've ever met, which made me feel great about myself.
Bad-I also think I maybe acted a little bit around her the same as with ENTP no. 1. She also decided to drop me by just ignoring me and any of my attempts to contact her. This may have been due to her misconstruing something I said over the internet and my accidentaly embarassing her a couple times in public, or her freaking out when the seriousness of our relationship suddenly accelerated when we had basically been glorified FWB's before. Nothing that couldn't of been discussed, but oh well. I found out after the fact(I still haven't deleted her on facebook for some reason) that she's a major pseudo-feminist and that her Fe mainifests itself through really pathetic whining, so maybe I dodged a little bit of a bullet.