Source of frustration

I just had what seemed like an innocent conversation, but it made me frustrated as hell. Why is that? I mean, sure the person I was talking to was pushing buttons, and in their own demented way, I'm sure they had fun imagining my brain boiling.
But, I'm wondering where this frustration came from. Stuff like constantly asking the same question over and over and over again usually doesn't make a difference - I either answer the question or I don't w/o feeling good or bad. But, this time it just drove me nuts.
I think it's b/c I felt taken advantage of, which is my own fault. I'm a pretty open guy, and share a lot - almost everything w. my friends. Which is probably why this person kept pushing. They're used to me talking about everything and everything.
I guess what's gotten me uptight is when I ask someone something and they don't want to talk about it, I let it slide after a couple of times. I mean sometime people say they don't want to talk about things to test how much you care. But, when they don't open up after a couple of attempts, I assume (bad word - makes an ASS out of U and ME) they're like me and really don't want to talk about it.
For me, I figure I'm open enough - what I do tell should be more than enough. But, we're not like that really, are we? When we do get something we like, we always want more - we're not satisfied w. just a taste... even if that taste is almost too much to handle. Just a bunch of junkies.

Anyway... this was just a rant. I'm not pissed off at my friend, or anything. Maybe more disappointed in myself for letting a little thing like that get to me. I'll do a little soul-searchin tonight to see if there is some underlying root here - or maybe I'm just tired. Both are OK... and both will be remedied sooner or later.

Happy reading.