i've had more than one person, generally exes or people who would become so, tell me that they felt they didn't know me. or that i didn't share enough or kept things or some variation. some said it matter of factly, some were upset, and at least one just put it out there as more of a philosophical discussion slash complaint about life in general.
and generally i think i'm pretty open and up front with people. especially people i purposefully bring in and try to keep in my life. coming from that general perspective..
that, to me, is part of the draw of others. mainly, to me, it is the gulf between them and me. i love discussion, debate, and listening. the attempt of seeing what makes up someone else.
but also it is the fact that i am only seeing a brief window. meet the same person years later (which i've also done) and it is a different experience.
and add on top of that you only ever know what people share of themselves. even in non-nefarious situations people only put out part of themselves, and you can only see/interpret part of that. it's like the moon in that you'll only see the side that is exposed. you'll never see the inner workings. and trying to can (sometimes but not always) be fun.