I have tons of acquaintances and those who might consider themselves my friends. I think the way I distinguish is this: If I don't worry about saying something stupid, then that person is truly my friend.
Yesterday, I had lunch with one of my closest friends, and I realized afterward that I don't have to censor myself at all when I'm with her. I can speak my mind and not worry about how it comes out -- I know she'll accept me regardless. The kiddos' auntie L is the same way. My mom is also like that, and my friends P and B and LR (my college roommate). DH, of course, as well. But...well, that's pretty much it.
The next level of friends are those whose company I definitely enjoy -- but I do have to watch what I say. I can't really be completely open, because I know there are things which will offend them. The moms at school fit into this category, along with my cousins (who are, in many ways, like my sisters -- BUT because they're so religious and I'm not, there are taboo areas). Sometimes, this isn't an issue at all. There are days where my brain and my mouth are 100% connected, and I can relax and know that my filter(s) are in place. Other days, however...well, you can probably imagine.
I don't see my cousins often enough for this to really be a problem; the moms at school, however, can be stressful. And the thing is, I truly enjoy some of them. I like hearing their thoughts and insights, and I enjoy working with them. But it still stresses me out because I have to be so careful not to say something stupid or offensive (often the thing which might be offensive is something I never even considered).
Maybe this is just part of being an introvert -- or maybe this is just me. When I'm tired (which is too often for comfort, especially in this area), my filter(s) are gone. Stuff just comes out, and afterward, I'm horrified. One of the moms I chatted with this weekend (the perfectionist) made the comment that she replays conversations in her head after and berates herself for all the stupid things she said. She thought that was a perfectionist trait -- but I had to admit that I do that too. I've had to work pretty hard sometimes to let it go (after all, it's already said and done) and not stress about possible hurts or frustrations I've given others through my words.
What say you? Is this an introvert thing, a creative thing, or just a Robin thing? :)